"I realized I was not alone": A mixed-methods investigation of the implementation of Ubuntu groups to reduce burnout and social isolation in an allopathic medical School in the Southeastern United States.

PURPOSE/BACKGROUND: Healthcare providers experience higher rates of workplace burnout, a reality highlighted by the COVID-19 pandemic. In response, small groups, inspired by South African philosophy, Ubuntu, were introduced to decrease burnout and social isolation and build community and belonging. This study examines how participation in these groups can impact these measures. METHODS: In this mixed-methods study, trained facilitators led small groups that utilized story-sharing to foster connections within the group and broader community. Quantitative and qualitative data were analyzed separately and merged to identify convergence. RESULTS: Three main qualitative themes emerged: 1) seeking and building connections and community, 2) curiosity, learning, and growing, and 3) open-hearted and thriving. These themes were linked to quantitative outcomes, showing a statistically significant decrease in social isolation among staff/faculty and students. Furthermore, faculty/staff exhibited reduced burnout compared to students, while students reported increased feelings of belonging. CONCLUSION: Participation in Ubuntu groups positively influenced students' sense of belonging, reduced faculty/staff burnout, and alleviated social isolation for all participants. Future research should explore the potential of this intervention to further promote wellness on medical campuses. Programs emphasizing the well-being of individuals, including faculty, staff, and students, are crucial for supporting the overall health of medical communities and the wider society.

SOARinG to New Heights Through a Structured Medical Student Research Program.

Introduction: Since the US Medical Licensing Examination (USMLE) Step 1 became Pass/Fall in 2022, medical students competing for residency spots must distinguish themselves with alternative criteria. Research experiences and output offer valuable skill development and objective metrics to support competitive residency applications. Objective: We describe the methodological development of a structured program to support, enhance, and track medical student research efforts at the University of South Carolina School of Medicine Greenville, explain the implementation of the program, and summarize initial program outcomes. Methods: The Student Opportunities for Academic Achievement Through Research in Greenville (SOARinG) Program was established to serve as a centralized hub for rising second year medical student research. The program matched medical students with mentored research projects scheduled during the summer following first-year coursework. The program included a required weekly seminar series on research basics and current biomedical literature. SOARinG culminated with a student research symposium for which students submitted abstracts and presented a poster or a talk. Quantitative and qualitative program outcomes of student and mentor satisfaction with the program were measured through surveys. Results and Discussion: The program was successfully implemented in summers 2021 and 2022. Most students (80-95%) in each class engaged in mentored summer research projects. Students reported overall satisfaction with research projects and mentor support. Overall, 69% of students rated their overall research experience in the program as extremely good or very good. Each student submitted an abstract and presented at the program's symposium or alternate research venue. Overall, 97% of research mentors reported that students were adequately prepared for summer research and suggested that students would benefit from additional skills-specific research training. Conclusion: The SOARinG Program provided a formalized process for tracking and showcasing medical student research and allowed for increased student participation in research. Additionally, each participating student produced objective research output, thus enhancing future residency applications.

Student Performance on Course Objectives in a First-Year Medical School Foundational Science Course Correlate with USMLE Step 1 Scores.

Purpose: Early identification of students at risk for poor United States Medical Licensing Examination® (USMLE) Step 1 examination (Step 1) performance allows medical schools to provide targeted intervention for those students. Therefore, determination of metrics that identify struggling students is necessary for proper intervention. We hypothesize that; 1) student performance on pre-matriculation metrics will correlate with their Molecular and Cellular Foundations of Medicine (FDNS) course performance and 2) student performance in the FDNS course and on specific FDNS course objectives will correlate with their Step 1 performance. Methods: This was a retrospective cohort study analyzing data for students matriculating to the University of South Carolina School of Medicine Greenville in 2018 and 2019. Linear regression analysis was conducted to assess the correlation between pre-matriculation metrics, performance in the FDNS course, performance on FDNS objectives, and USMLE Step 1 performance. Adjusted R-squared (adjusted r2) values were compared with a p-value at <0.05. Results: The FDNS course grade correlated with pre-matriculation metrics of science undergraduate grade point average (uGPA), total uGPA, and the Medical College Admission Test (MCAT), adjusted r2 of 0.139, 0.121, 0.223, respectively. The FDNS course grade showed a stronger correlation to USMLE Step 1 performance (adjusted r2 = 0.257) than pre-matriculation metrics. USMLE Step 1 performance strongly correlated with FDNS course performance when two objectives, pertaining to anabolic and catabolic processes, regulation of cell cycle, and DNA replication and repair, were combined, adjusted r2 of 0.357. Conclusion: The FDNS course grade and performance on specific course objectives could serve as a predictor for USMLE Step 1 performance and provides a more targeted and concise approach to identification of low-performing students and subsequent intervention.

Research Education Program for Underrepresented Minority Students: Students' Perception of Academic Enrichment and Research Activities.

The Research Education Program (REP) is an NIH R25-funded training grant designed to increase the pipeline of underrepresented minority (URM) students entering graduate programs and pursuing biomedical research and health care careers. Each week, students participated in different academic enrichment activities during morning sessions. Research activities were during afternoon sessions. URM students presented their research findings in a local poster session with their peers, graduate medical students, and faculty members. They also attended national conferences to gain experience and expand their professional networks. Our participants included 14.3% rural, 42.85% suburban, and 42.85% urban students. Of this, 83.33% were females, while 16.67% were males. In addition, 100% of students indicated exceptional satisfaction in 64.0% of the academic enrichment activities offered by the REP, and 100% indicated exceptional satisfaction in 63.0% of the research activities. Future research will investigate the long-term effects of REP and graduate enrollments.

Apoptotic qPCR gene expression array analysis demonstrates proof-of-concept for rapid blastocoel fluid-conditioned media molecular prediction.

PURPOSE: Successful identification of transcriptomic biomarkers within human IVF embryos may enhance implantation prediction and provide insights not available through conventional embryo biopsy genomic analysis. We demonstrate proof-of-concept for a methodology to assess overall embryo gene expression using qPCR with blastocoel fluid-conditioned media by examining the comparative presence of apoptotic genes. METHODS: Blastocoel fluid-conditioned media were collected from 19 embryos (11 euploid) following trophectoderm biopsy of day-5 ICSI-IVF blastocysts. Media were assessed for apoptotic gene expression via qPCR. Statistical analysis of gene expression was conducted via Wilcoxon Signed-Ranks test (overall expression), multivariate ANOVA (functional gene groups), and chi-square test of independence (gene level). RESULTS: A significantly higher overall apoptotic gene expression within euploid versus aneuploid embryos (p = 0.001) was observed. There was significantly (p = 0.045) higher expression of pro-apoptotic genes between implanted and not implanted embryos. Pro- vs. anti-apoptotic gene expression from all euploid embryos approached significance (p = 0.053). The ploidy status-based claim is further substantiated at the gene level with significantly higher expression of BBC3 (p = 0.012) and BCL2L13 (p = 0.003) in euploid embryos compared to aneuploid embryos. CONCLUSIONS: In this preliminary study, we demonstrate that (1) qualitative analysis of blastocoel fluid-conditioned media gene expression is possible, (2) global trends of expression are potentially related to clinical outcomes, and (3) gene-level expression trends exist and may be another viable metric for comparative expression between samples. The presence of statistical significance within analyses conducted with this sample size warrants a larger investigation of blastocoel fluid-conditioned media as an additional beneficial predictive tool for future IVF cases.

The expression of pregnancy-associated plasma protein-A (PAPP-A) in human blastocoel fluid-conditioned media: a proof of concept study.

PURPOSE: The aim of this study was to determine if pregnancy-associated plasma protein-A (PAPP-A), typically measured in maternal serum and a potential predictor of adverse maternal and fetal outcomes such as spontaneous miscarriage, pre-eclampsia, and stillbirth, is expressed in blastocoel fluid-conditioned media (BFCM) at the embryonic blastocyst stage. DESIGN: This is an in vitro study. METHODS: BFCM samples from trophectoderm-tested euploid blastocysts (n = 80) from in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) patients were analyzed for PAPP-A mRNA. BFCM was obtained from blastocyst stage embryos in 20 uL drops. Blastocysts underwent trophectoderm biopsy for preimplantation genetic testing for aneuploidy prior to blastocyst vitrification and BFCM collection for snap freezing. cfDNA was synthesized using BFCM collected from 80 individual euploid blastocysts. Next, real-time qPCR was performed to detect expression of PAPP-A with GAPDH for normalization of expression in each sample. RESULTS: PAPP-A mRNA was detected in 45 of 80 BFCM samples (56.3%), with varying levels of expression across samples. CONCLUSION: Our study demonstrates the expression of PAPP-A in BFCM. To our knowledge, this is the first study to report detection of PAPP-A mRNA in BFCM. Further studies are required and underway to investigate a greater number of BFCM samples as well as the possible correlation of PAPP-A expression with pregnancy outcomes of transferred euploid blastocysts. If found to predict IVF and obstetric outcomes, PAPP-A may provide additional information along with embryonic euploidy for the selection of the optimal blastocyst for embryo transfer.

Comparison of RNA content from hydrophobic interaction chromatography-isolated seminal plasma exosomes from intrauterine insemination (IUI) pregnancies.

Male factors account for roughly half of infertility cases, with most male infertility diagnosed as idiopathic. Researchers predicting intrauterine insemination success rates have identified multiple prognostic factors, including semen parameters and seminal fluid composition. Seminal plasma contains extracellular exosomes, which contain RNAs and proteins involved in spermatogenesis. The contents of seminal plasma exosomes may be an indicator of overall sperm quality or fertility potential; therefore, analysis of exosomes may provide a measure for sperm viability and fertilization potential. In our study, exosomes were isolated and purified from seminal plasma obtained from IUI treatments with known pregnancy outcomes. We used a unique method to isolate the exosomes which made use of the hydrophobic interaction chromatography method. RNASeq was performed on RNAs from the purified exosomes. This analysis revealed holistic trends, including increased expression associated with RNA originating from chromosomes 1, 10, 12, 16 and 21. Overall, total RNA was significantly decreased and rRNA was significantly increased in successful IUI attempts. Furthermore, we found specific mRNAs and lincRNAs associated with positive versus negative pregnancy outcomes. Our study isolated and purified seminal plasma exosomes without ultracentrifugation, and it provides further evidence for differences in seminal plasma exosome molecular contents associated with pregnancy status.

Metabolomic Profiles of Men and Women Ischemic Stroke Patients.

BACKGROUND: Stroke is known to affect both men and women; however, incidence and outcomes differ between them. Therefore, the discovery of novel, sex-specific, blood-based biomarkers for acute ischemic stroke (AIS) patients has the potential to enhance the understanding of the etiology of this deadly disease in the content of sex. The objective of this study was to identify serum metabolites associated with male and female AIS patients. METHODS: Metabolites were measured with the use of untargeted, reverse-phase ultra-performance liquid chromatography-tandem mass spectrometry quantification from blood specimens collected from AIS patients. Samples were collected from 36 patients comprising each of 18 men and women with matched controls. Metabolic pathway analysis and principal component analysis (PCA) was used to differentiate metabolite profiles for male and female AIS patients from the control, while logistic regression was used to determine differences in metabolites between male and female AIS patients. RESULTS: In female AIS patients, 14 distinct altered metabolic pathways and 49 corresponding metabolites were identified, while 39 metabolites and 5 metabolic pathways were identified in male patients. Metabolites that are predictive of ischemic stroke in female patients were 1-(1-enyl-palmitoyl)-2-arachidonoyl-GPC (P-16:0/20:4) (AUC = 0.914, 0.765-1.000), 1-(1-enyl-palmitoyl)-2-palmitoyl-GPC (P-16:0/16:0) (AUC = 0.840, 0.656-1.000), and 5,6-dihydrouracil (P-16:0/20:2) (AUC = 0.815, 0.601-1.000). Significant metabolites that were predictive of stroke in male patients were 5alpha-androstan-3alpha,17beta-diol disulfate (AUC = 0.951, 0.857-1.000), alpha-hydroxyisocaproate (AUC = 0.938, 0.832-1.000), threonate (AUC = 0.877, 0.716-1.000), and bilirubin (AUC = 0.817, 0.746-1.000). CONCLUSIONS: In the current study, the untargeted serum metabolomics platform identified multiple pathways and metabolites associated with male and female AIS patients. Further research is necessary to characterize how these metabolites are associated with the pathophysiology in male and female AIS patients.

Comparative analysis of viral infection outcomes in human seminal fluid from prior viral epidemics and Sars-CoV-2 may offer trends for viral sexual transmissibility and long-term reproductive health implications.

BACKGROUND: Viral detection in seminal fluid indicates their potential for both sexual transmission and impairment of reproductive health. Review of the mechanistic entry, sexual transmission and viral impacts for patients during major recent viral outbreaks of Zika virus (ZIKV), Ebola virus (EBOV), severe acute respiratory syndrome (SARS)-coronavirus (CoV), and SARS-coronavirus 2 (CoV-2) (the virus which causes COVID-19) provides a framework to discuss this potential. AIM: Comparative analysis of prior viral presence on seminal fluid against current (preliminary) findings for SARS-CoV-2 to predict biological implications of the novel coronavirus upon current sexual transmissibility, viral presence, and reproductive health. METHODOLOGY AND FINDINGS: Literature review was conducted using PubMed and Google Scholar databases. ZIKV and EBOV were found to be present in semen and to be sexually transmitted, leading the World Health Organization (WHO) to update their guidelines on prevention of the two viruses to include refraining from sexual contact. There are conflicting studies regarding the presence of SARS-CoV in male reproductive tissue, but it has been linked to testicular atrophy and orchitis. To date, two studies have detected SARS-CoV-2 RNA in semen, while seven studies have reported no positive detection. CONCLUSIONS: Though unlikely in the majority of cases, SARS-CoV-2 can potentially be present in seminal fluid, although there are no reports of sexual transmission to date. Prior epidemics raise significant concerns regarding the long-term reproductive health capacity for patients who are affected by entry of Sars-CoV-2 into the reproductive tract, therefore more study is needed to clarify the impacts to reproductive health.

This review describes the detection of viruses in seminal fluid and their sexual transmission, focusing on the major viral outbreaks of Zika virus (ZIKV), Ebola virus (EBOV), severe acute respiratory syndrome (SARS)-coronavirus (CoV), and SARS-coronavirus 2 (CoV-2). ZIKV and EBOV were found to be present in semen and to be sexually transmitted, leading the World Health Organization (WHO) to update their guidelines on prevention of the two viruses to include refraining from sexual contact. There are conflicting studies regarding the presence of SARS-CoV in male reproductive tissue, but it has been linked to testicular atrophy and orchitis. To date, two studies have detected SARS-CoV-2 RNA in semen, while seven studies have reported no positive detection. More studies must be completed to accurately determine its risk of sexual transmission to ensure mitigation of further transmission and understand the long-term implications of SARS-CoV-2 on the reproductive health of recovered patients.

Patient engagement in fertility research: bench research, ethics, and social justice.

BACKGROUND: Patient and Public Involvement (PPI) in research is increasingly being utilized to better connect patients and researchers. The Patient Engagement Studio (PES) supports PPI in research by working directly with researchers throughout various stages of their projects. Recently, two researchers presented to the PES for assistance with their project, Embryo+™. The purpose of Embryo+™ is to decrease miscarriage rates using RNA sequencing technology that screens for the most viable embryos. To date, no examples of PPI directly in the planning or implementation of bench research concerning in vitro fertilization and embryo transfer have been identified. MAIN BODY: Embryo+™ researchers met in-person with the PES two times (fall 2019; each meeting had 9 PES members in attendance) for initial feedback and protocol development. After these meetings, PES leadership and Embryo+™ researchers decided that the unique nature of the project merited a PPI evaluation. Subsequent evaluation of engagement efforts occurred by reviewing the PES reports for the Embryo+™ researchers, conducting two recorded web-based discussion meetings with the PES (summer 2020; meeting 1 n = 7; meeting 2 n = 6), and a brief survey (n = 13). The discussion meetings provided an opportunity for the PES members to define engagement themes through consensus via verbal agreement to the studio director's periodic summaries during the discussions. Combining survey results and PES themes allowed for a broad discussion for meaningful engagement. The Embryo+™ researchers established trust with the patients by changing some of their language in response to patient suggestions, allowing for unintended ethical conversations, and implementing the patient developed protocols. Overall, the patient experts thought this project was very meaningful and valuable, quantified by a mean loyalty score 89.43 (s.d. 10.29). CONCLUSION: Bench science researchers may need additional PPI training prior to engaging with patient groups. PPI in this project was successful in large part due to this training, where the director emphasized the importance of gaining trust with the patients. The researchers applied what they learned and several examples of how to develop trust with patients are discussed. If trust is established, PPI in an ethically charged, basic science research study can be both valuable and successful.

Patients are increasingly becoming involved in all stages of the research process. Patient and public involvement has been shown to answer questions that matter to patients, increase enrollment in studies, and improve the spread of research results to the public. However, there are limited evaluations of patient engagement in basic science research (research performed in a laboratory setting in various fields). Here, we provide an example of patients effectively involved in the planning and implementation of an ethically complex study in the field of Assistive Reproductive Technology. A Patient Engagement Studio, affiliated with an academic health center, directly connects patients and researchers through bi-monthly meetings. Recently, two researchers presented their project, Embryo+™, to the studio during the planning stage of their study. This project aims to use a new testing technology to reduce miscarriage rates. The researchers presented to the studio twice (fall 2019), and two follow-up meetings were conducted with the patients (summer 2020). Also, the patients completed a survey evaluating how engaged they felt with the project. Through the meetings, the researchers changed their language in response to patient feedback, and patients developed project protocols. Survey results showed that the patients thought this project was very meaningful and valuable. Overall, this evaluation shows that patients can add value to contentious bench science projects, particularly in the field of Assistive Reproductive Technology.

Fluorescent-dependent comparative Ct method for qPCR gene expression analysis in IVF clinical pre-implantation embryonic testing.

The use of quantitative PCR (qPCR) and other polymerase chain reaction (PCR)-based methods in the field of human in vitro fertilization blastocoel fluid analysis can potentially be utilized for assisting clinicians in embryo selection based on specific gene expression patterns. Since typical Comparative cycle threshold (Ct ) analysis utilizes one threshold for runs per gene target and requires an inherent control group, this method is inadequate for analysis of small stochastic systems, such as embryonic-derived fluid. We mathematically demonstrate analytical modifications upon the Comparative Ct qPCR workflow to incorporate a variable fluorescence threshold (utilizing only the parameters defined in the Comparative Ct method), and subsequently demonstrate the typical workflow in which this modified method can successfully quantifiably analyze embryonic blastocoel fluid qPCR analysis.

Two Acinetobacter baumannii Isolates Obtained From a Fatal Necrotizing Fasciitis Infection Display Distinct Genomic and Phenotypic Characteristics in Comparison to Type Strains.

Acinetobacter baumannii has been recognized as a critical pathogen that causes severe infections worldwide not only because of the emergence of extensively drug-resistant (XDR) derivatives, but also because of its ability to persist in medical environments and colonize compromised patients. While there are numerous reports describing the mechanisms by which this pathogen acquires resistance genes, little is known regarding A. baumannii's virulence functions associated with rare manifestations of infection such as necrotizing fasciitis, making the determination and implementation of alternative therapeutic targets problematic. To address this knowledge gap, this report describes the analysis of the NFAb-1 and NFAb-2 XDR isolates, which were obtained at two time points during a fatal case of necrotizing fasciitis, at the genomic and functional levels. The comparative genomic analysis of these isolates with the ATCC 19606T and ATCC 17978 strains showed that the NFAb-1 and NFAb-2 isolates are genetically different from each other as well as different from the ATCC 19606T and ATCC 17978 clinical isolates. These genomic differences could be reflected in phenotypic differences observed in these NFAb isolates. Biofilm, cell viability and flow cytometry assays indicate that all tested strains caused significant decreases in A549 human alveolar epithelial cell viability with ATCC 17978, NFAb-1 and NFAb-2 producing significantly less biofilm and significantly more hemolysis and capacity for intracellular invasion than ATCC 19606T. NFAb-1 and NFAb-2 also demonstrated negligible surface motility but significant twitching motility compared to ATCC 19606T and ATCC 17978, likely due to the presence of pili exceeding 2 µm in length, which are significantly longer and different from those previously described in the ATCC 19606T and ATCC 17978 strains. Interestingly, infection with cells of the NFAb-1 isolate, which were obtained from a premortem blood sample, lead to significantly higher mortality rates than NFAb-2 bacteria, which were obtained from postmortem tissue samples, when tested using the Galleria mellonella in vivo infection model. These observations suggest potential changes in the virulence phenotype of the A. baumannii necrotizing fasciitis isolates over the course of infection by mechanisms and cell processes that remain to be identified.

Retention of Biomedical Knowledge in Medical Students Predicts USMLE Step 1 Scores.

This article was migrated. The article was marked as recommended. Introduction Medical students are tasked with learning a vast amount of medical knowledge prior to sitting for the USMLE Step 1 exam, a portion of which is either forgotten or becomes inaccessible to memory following each exam. In this study we examined whether accessibility and retention of 1 st-year biochemistry content predicts performance on high stakes exams such as USMLE Step1. Methods First-year medical students were retested on a subset of biochemistry final exam items 10.5 months after sitting for the original exam. Retention was measured as a percentage of the original final exam score. Availability of information was measured with cued recall (i.e., selecting from a list the multiple-choice distractors), while accessibility of information was captured through free recall (without the aid of multiple choice distractors). Results As expected, we found that free recall rates were much lower than cued recall rates, but that students who scored higher on Step 1 had a smaller gap between cued and free recall scores, demonstrating a greater ability to access information than lower-scoring students. Importantly, we also demonstrate that higher-scoring students retained a higher percentage of the original biochemistry material than lower-performing students after 10.5 months, and that the amount information retained in memory was associated with higher scores on Step 1, demonstrating the potential importance of teaching medical school content with the intention of making it stick, especially in students who are not as strong academically. Conclusion The methods employed in this study are straightforward and can be used to compare retention and accessibility of information across medical school courses, and may serve as a guide to curriculum and pedagogical improvements.

Embryo Biopsy Can Offer More Information Than Just Ploidy Status.

As a byproduct of increasing infertility cases, the use of medically assisted reproduction (MAR) has increased. As such, the need to gain information regarding the implantation potential of specific MAR preimplantation embryos prior to transfer has become increasingly critical. One potential source of this information is contained in the blastocoel fluid from day 5/6 embryos. This fluid contains cell-free DNA, proteins, RNA, metabolites, exosomes, etc., and analysis of these contents provides clinicians with an opportunity to gain more data regarding potential of each embryo. While application of preimplantation genetic testing for aneuploidies (PGT-A) may be limited to women of advanced maternal age or with recurrent pregnancy loss, the fluid taken at the time of embryo biopsy can be analyzed for any frozen embryo as well as PGT-A embryos. In both cases, blastocoel fluid analysis provides information regarding a preimplantation embryo's potential for implantation. Moreover, as remnants of apoptosis, embryonic cell-free DNA (cfDNA) and mRNA may lead clinicians to better understand and predict the extent of self-correction occurring within the preimplantation embryo. While analysis of blastocoel components are not yet viable replacements for PGT-A, their study may still reveal critical clinical information about the implantation potential for any given embryo.

Relationship between blastocoel cell-free DNA and day-5 blastocyst morphology.

PURPOSE: Cell-free DNA (cfDNA) which is present in the blastocoel cavity of embryos is believed to result from physiological apoptosis during development. This study assessed cfDNA content and caspase-3 protease activity in day-5 IVF blastocysts to determine if there was a correlation with embryo morphology. METHODS: Day-5 IVF blastocysts were scored according to the Gardner and Schoolcraft system (modified to generate a numerical value) and cfDNA was collected following laser-induced blastocoel collapsing prior to cryopreservation in 25 µL of media. cfDNA was quantified via fluorospectrometry and apoptotic activity was assessed via a caspase-3 protease assay using a fluorescent peptide substrate. Data were compared by linear regression. RESULTS: A total of 32 embryos were evaluated. There was a significant (p < 0.01) and positive correlation (cfDNA = 104.753 + (11.281 × score); R2 = 0.200) between embryo score and cfDNA content. A significant (p < 0.05) and positive correlation (cfDNA = 115.9 + (0.05 × caspase-3); R2= 0.128) was observed between caspase-3 activity and cfDNA levels. There was no significant relationship between caspase-3 activity and embryo morphology score. CONCLUSIONS: This study provides further evidence that cfDNA is present in blastocoel fluid, can be quantified, and positively correlates with embryonic morphology. There is also evidence that at least a portion of the cfDNA present is from intracellular contents of embryonic cells that underwent apoptosis. Additional studies are warranted to determine other physiological sources of the cfDNA in blastocyst fluid and to determine the relationship with cfDNA content, embryo morphology, and chromosomal ploidy status plus implantation potential.

Histone H3K4 methylation regulates deactivation of the spindle assembly checkpoint through direct binding of Mad2.

Histone H3 methylation on Lys4 (H3K4me) is associated with active gene transcription in all eukaryotes. In Saccharomyces cerevisiae, Set1 is the sole lysine methyltransferase required for mono-, di-, and trimethylation of this site. Although H3K4me3 is linked to gene expression, whether H3K4 methylation regulates other cellular processes, such as mitosis, is less clear. Here we show that both Set1 and H3K4 mutants display a benomyl resistance phenotype that requires components of the spindle assembly checkpoint (SAC), including Bub3 and Mad2. These proteins inhibit Cdc20, an activator of the anaphase-promoting complex/cyclosome (APC/C). Mutations in Cdc20 that block Mad2 interactions suppress the benomyl resistance of both set1 and H3K4 mutant cells. Furthermore, the HORMA domain in Mad2 directly binds H3, identifying a new histone H3 "reader" motif. Mad2 undergoes a conformational change important for execution of the SAC. We found that the closed (active) conformation of both yeast and human Mad2 is capable of binding methylated H3K4, but, in contrast, the open (inactive) Mad2 conformation limits interaction with methylated H3. Collectively, our data indicate that interactions between Mad2 and H3K4 regulate resolution of the SAC by limiting closed Mad2 availability for Cdc20 inhibition.

Chromatin signaling to kinetochores: transregulation of Dam1 methylation by histone H2B ubiquitination.

Histone H3K4 trimethylation by the Set1/MLL family of proteins provides a hallmark for transcriptional activity from yeast to humans. In S. cerevisiae, H3K4 methylation is mediated by the Set1-containing COMPASS complex and is regulated in trans by prior ubiquitination of histone H2BK123. All of the events that regulate H2BK123ub and H3K4me are thought to occur at gene promoters. Here we report that this pathway is indispensable for methylation of the only other known substrate of Set1, K233 in Dam1, at kinetochores. Deletion of RAD6, BRE1, or Paf1 complex members abolishes Dam1 methylation, as does mutation of H2BK123. Our results demonstrate that Set1-mediated methylation is regulated by a general pathway regardless of substrate that is composed of transcriptional regulatory factors functioning independently of transcription. Moreover, our data identify a node of regulatory crosstalk in trans between a histone modification and modification on a nonhistone protein, demonstrating that changing chromatin states can signal functional changes in other essential cellular proteins and machineries.

A two-way street: LSD1 regulates chromatin boundary formation in S. pombe and Drosophila.

Two recent studies in Molecular Cell (Lan et al., 2007; Rudolph et al., 2007) implicate histone demethylation by LSD1 in the regulation of boundaries between silenced and active chromatin domains in both fission yeast and flies, but by distinct mechanisms.

Structural analysis of Xanthomonas XopD provides insights into substrate specificity of ubiquitin-like protein proteases.

XopD (Xanthomonas outer protein D), a type III secreted effector from Xanthomonas campestris pv. vesicatoria, is a desumoylating enzyme with strict specificity for its plant small ubiquitin-like modifier (SUMO) substrates. Based on SUMO sequence alignments and peptidase assays with various plant, yeast, and mammalian SUMOs, we identified residues in SUMO that contribute to XopD/SUMO recognition. Further predictions regarding the enzyme/substrate specificity were made by solving the XopD crystal structure. By incorporating structural information with sequence alignments and enzyme assays, we were able to elucidate determinants of the rigid SUMO specificity exhibited by the Xanthomonas virulence factor XopD.