Oxford nanopore sequencing-based assay for BTD gene screening: Design, clinical validation, and variant frequency assessment in the Turkish population.

Biotinidase deficiency (BTD) is an autosomal recessive disorder characterized by impaired recycling of the water-soluble vitamin biotin which leads to a spectrum of clinical manifestations ranging from mild to severe, including mainly neurological and cutaneous symptoms. Biotin supplementation is a cornerstone of treatment, but diagnosis often relies on measuring serum enzyme activity, which needs to be confirmed by genetic analysis. Thus, molecular methods become necessary in the differential diagnosis of BTD. Accordingly, countries with a high-incidence have implemented next-generation sequencing (NGS) techniques to newborn screening programs for BT. Nevertheless, NGS platforms, while well-established, present challenges in cost, labor, accessibility, and duration for newborn screening programs targeting BTD, therefore these limitations necessitate the exploration of alternative systems to ensure efficient and widespread screening. Here, third-generation sequencing platforms, notably Oxford Nanopore Technology (ONT), present promising solutions to the associated challenges. Hence, in the present study, we aimed to develop an ONT-based assay for the screening of BTD gene. After designing and optimizing primers for long-PCR using reference DNA, we assessed the performance of the ONT assay in BTD patients previously diagnosed by enzyme assay and confirmed using Illumina-based sequencing. The results demonstrate a strong correlation between the two methods, indicating the reliability of the ONT-based assay. Moreover, this first in-house single gene testing specifically tailored for BTD successfully detected previously known genetic variants with high sequencing depths, affirming the effectiveness of ONT-based sequencing in human genetics.

Differential synergistic effects of palbociclib and doxorubicin on doxorubicin-resistant cancer cells with diverse tumor origins.

Palbociclib is a dual inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6). Palbociclib has frequently been studied in breast cancer cells and has also been linked to function of P-glycoprotein (P-gp), main protein responsible for cancer drug resistance. However, the effect of Palbociclib on cancer drug resistance and specifically doxorubicin-resistant cells overexpressing P-gp have limitedly been studied in the literature. Here, we aimed to decipher the possible synergistic effects of Palbociclib and Doxorubicin combination treatment in doxorubicin-resistant not only breast cancer, which has restrictedly been studied previously, but leukemia and cervical cancer cell lines in the presence of sensitive counterparts to totally explore the mechanistic properties of the Palbociclib in cancer drug resistance. Our results underlined that Palbociclib differentially displayed synergistic effect with doxorubicin in a cell type-specific manner and increased the efficacy of Doxorubicin in Doxorubicin-resistant cells. As a monotherapy, palbociclib has been shown to decrease the expression of MDR-1 in doxorubicin-resistant cells, and when used in combination with doxorubicin, it has been shown to increase the accumulation of doxorubicin in the cell and consequently induce apoptosis. This is the first report that proposes the Palbociclib as a candidate for combination therapy to limit the Doxorubicin resistance in different cancer origins in clinics.

The interrelation between the high expression level of MIR34a and the trisomic abortion materials.

AIMS: The underlying mechanism and constitution of spontaneous abortions are complicated and heterogeneous. Many factors, including epigenetic scenarios like micro-ribonucleic acids (miRNAs, MIRs), can additively affect the progression of pregnancy losses. This study aimed to evaluate whether the expression levels of placental inhibitor and/or activator miRNAs had a difference between the numerically abnormal and normal karyotyped spontaneous abortions. METHODS: The case-control study included 100 spontaneous abortion materials consisting of trophoblastic tissues with 42 disomies (controls), 43 aneuploidies (including trisomy 16, 21, 22, and monosomy X), and 15 triploidies. Disomic abortion materials with XX normal karyotypes were omitted from the study to exclude possible maternal decidual cell contamination. Total RNA isolation was performed with TRIzol™ reagent directly from frozen trophoblastic tissues, and the mature miRNAs were obtained by reverse transcription via quantitative real-time polymerase chain reaction (qRT-PCR). Then, the expression levels of placental activators MIR378a-5p, MIR376c, MIR195, and inhibitors MIR34a and MIR210 were relatively evaluated using MIR130 as a reference. RESULTS: The expression level of placental inhibitor MIR34a was detected to be high in trisomic abortion materials (trisomy 16 and 21) when compared to the disomic ones (p = 0.0324). MIR195 (p = 0.0484) and MIR34a (p = 0.0346) expression levels were increased in numerically abnormal cases with advanced maternal age compared to the disomic ones within all maternal ages. CONCLUSIONS: It seems likely that the high expression level of MIR34a and the coexistence of trisomic abortion materials are quite interrelated with the additive effect of advanced maternal age.

Athletic performance, sports experience, and exercise addiction: an association study on ANKK1 gene polymorphism rs1800497.

Introduction: Exercise addiction is a phenomenon being able to affecting the athletic performance. The gene, ANKK1 and the polymorphism NM_178510.2:c.2137G > A (rs1800497) has been linked to the exercise addiction. However, further studies on diverse populations and sport branches are needed to totally explore the possible association of this polymorphism with the athletic performance. Thus, the present study aims to decipher any possible relations of the rs1800497 polymorphism with the athletic performance/personal best (PB) and sport experience of elite athletes. Methods: Sixty volunteer elite athletes (31 sprint/power and 29 endurance) and 20 control/sedentary participated in the study. The polymorphism was genotyped using whole exome sequencing approach and PB were determined according to the International Association of Athletics Federations (IAAF) score. Results: Our results underlined that there were not any significance differences for both allele and genotype frequencies between the groups in terms of athletic performance, although the frequency of allele G was higher (p > 0.05). Nevertheless, sport experience significantly associated with the rs1800496 polymorphism (p < 0.05). Discussion: In conclusion, genotype G/G could be inferred to be linked to the higher sport experience and athletic performance. Still, further studies with higher number of participants are needed to conclude the association of this polymorphism with athletic parameters.

Association of ACTN3 R577X Polymorphism with Elite Basketball Player Status and Training Responses.

The α-actinin-3 (ACTN3) gene rs1815739 (C/T, R577X) polymorphism is a variant frequently associated with athletic performance among different populations. However, there is limited research on the impact of this variant on athlete status and physical performance in basketball players. Therefore, the aim of this study was twofold: (1) to determine the association of ACTN3 rs1815739 polymorphism with changes in physical performance in response to six weeks of training in elite basketball players using 30 m sprint and Yo-Yo Intermittent Recovery Test Level 2 (IR 2) tests, and (2) to compare ACTN3 genotype and allelic frequencies between elite basketball players and controls. The study included a total of 363 individuals, comprising 101 elite basketball players and 262 sedentary individuals. Genomic DNA was isolated from oral epithelial cells or leukocytes, and genotyping was performed by real-time PCR using KASP genotyping method or by microarray analysis. We found that the frequency of the ACTN3 rs1815739 XX genotype was significantly lower in basketball players compared to controls (10.9 vs. 21.4%, p = 0.023), suggesting that RR/RX genotypes were more favorable for playing basketball. Statistically significant (p = 0.045) changes were observed in Yo-Yo IRT 2 performance measurement tests in basketball players with the RR genotype only. In conclusion, our findings suggest that the carriage of the ACTN3 rs1815739 R allele may confer an advantage in basketball.

Exome-Wide Association Study of Competitive Performance in Elite Athletes.

The aim of the study was to identify genetic variants associated with personal best scores in Turkish track and field athletes and to compare allelic frequencies between sprint/power and endurance athletes and controls using a whole-exome sequencing (WES) approach, followed by replication studies in independent cohorts. The discovery phase involved 60 elite Turkish athletes (31 sprint/power and 29 endurance) and 20 ethnically matched controls. The replication phase involved 1132 individuals (115 elite Russian sprinters, 373 elite Russian endurance athletes (of which 75 athletes were with VO2max measurements), 209 controls, 148 Russian and 287 Finnish individuals with muscle fiber composition and cross-sectional area (CSA) data). None of the single nucleotide polymorphisms (SNPs) reached an exome-wide significance level (p < 2.3 × 10-7) in genotype-phenotype and case-control studies of Turkish athletes. However, of the 53 nominally (p < 0.05) associated SNPs, four functional variants were replicated. The SIRT1 rs41299232 G allele was significantly over-represented in Turkish (p = 0.047) and Russian (p = 0.018) endurance athletes compared to sprint/power athletes and was associated with increased VO2max (p = 0.037) and a greater proportion of slow-twitch muscle fibers (p = 0.035). The NUP210 rs2280084 A allele was significantly over-represented in Turkish (p = 0.044) and Russian (p = 0.012) endurance athletes compared to sprint/power athletes. The TRPM2 rs1785440 G allele was significantly over-represented in Turkish endurance athletes compared to sprint/power athletes (p = 0.034) and was associated with increased VO2max (p = 0.008). The AGRN rs4074992 C allele was significantly over-represented in Turkish sprint/power athletes compared to endurance athletes (p = 0.037) and was associated with a greater CSA of fast-twitch muscle fibers (p = 0.024). In conclusion, we present the first WES study of athletes showing that this approach can be used to identify novel genetic markers associated with exercise- and sport-related phenotypes.

Evaluation of the Association of VDR rs2228570 Polymorphism with Elite Track and Field Athletes' Competitive Performance.

The present study aimed to examine the vitamin D receptor (VDR), rs2228570 polymorphism, and its effect on elite athletes' performance. A total of 60 elite athletes (31 sprint/power and 29 endurance) and 20 control/ physically inactive, aged 18-35, voluntarily participated in the study. The International Association of Athletics Federations (IAAF) score scale was used to determine the performance levels of the athletes' personal best (PB). Whole exome sequencing (WES) was performed by the genomic DNA isolated from the peripheral blood of the participants. Sports type, sex, and competitive performance were chosen as the parameters to compare within and between the groups by linear regression models. The results showed no statistically significant difference between the CC, TC, and TT genotypes within and between the groups (p > 0.05). Additionally, our results underlined that there were no statistically significant differences for the association of rs2228570 polymorphism with PBs within the groups of the (p > 0.05) athletes. The genetic profile in the selected gene was similar in elite endurance, sprint athletes, and in controls, suggesting that rs2228570 polymorphism does not determine competitive performance in the analyzed athlete cohort.

Microglial iron trafficking: new player in brain injury.

BACKGROUND: Neonatal brain injury is a significant reason of neurodevelopmental abnormalities and long-term neurological impairments. Hypoxic-ischemic encephalopathy and preterm brain injury, including intraventricular hemorrhage are the most common grounds of brain injury for full-term and preterm neonates. The prevalence of hypoxic ischemic encephalopathy varies globally, ranging from 1 to 3.5/1000 live births in high-resource countries and 26/1000 in low-resource countries. Preterm birth's global incidence is 15 million, a significant reason for infant mortality and morbidity, permanent neurologic problems, and the associated social and economic burden. The widespread neurodevelopmental effects of neonatal brain injury could have an unfavorable impact on a variety of aspects of cognitive, linguistic, behavioral, sensory, and motor functions. Brain injury occurs via various mechanisms, including energy deprivation, excitatory amino acids, mitochondrial dysfunction, reactive oxygen species, and inflammation giving rise to different forms of cell death. The contribution of microglial activity in neonatal brain injury has widely been underlined by focusing on cell death mechanisms since the neuronal death pathways during their development are distinct from those in the adult brain. Iron accumulation and lipid peroxidation cause a relatively novel type of regulated cell death called ferroptosis. Neonates generally have biochemical iron inequalities, and their antioxidant potential is highly restricted, implying that ferroptosis may be significant in pathologic conditions. Moreover, inhaled nitric oxide therapy in infants may lead to microglial inflammation via ferroptosis and neuronal injury in the developing brain. This review article aims to summarize the studies that investigated the association between neonatal brain injury and iron metabolism, with a particular emphasis on the microglial activity and its application to the inhibition of neonatal brain injury.

A de novo heterozygous HOXA11 variant in a patient with mesomelic dysplasia with urogenital abnormalities.

Mesomelic dysplasias are a genetically and clinically heterogeneous group of diseases with more than 10 types defined. This article presents an 18-year-old female patient with normal intelligence and a multisystem phenotype including disproportionate short stature, scoliosis, mesomelic limb shortening, radial bowing, short fourth to fifth metacarpals and metatarsals, fusions in the carpal/tarsal bones, operated pes equinovarus, primary amenorrhea, uterine hypoplasia, vesicoureteral reflux, and chronic kidney disease. Whole-exome sequencing revealed a de novo heterozygous c.881T>G (p.Met294Arg) variant in HOXA11 (NM_005523.6) gene. The variant was located in the homeodomain of HOXA11 and predicted to alter DNA-binding ability of the protein. In silico analyses indicated that the variant could promote the alterations in the protein-protein interaction. The possible functional effect of the variant was supposed as dominant-negative. Hoxa11-mutant mice have been reported to exhibit homeotic transformations in the thoracic and sacral vertebrae, zeugopodal phenotype in forelimb and hindlimb, and urogenital abnormalities. Although mice models were reported as mesomelic dysplasia and urogenital abnormalities (MDUGA), this phenotype has not yet been reported in humans. This was the first case with MDUGA putatively related to a de novo variant in HOXA11.

Ultimate COVID-19 Detection Protocol Based on Saliva Sampling and qRT-PCR with Risk Probability Assessment.

In the era of COVID-19 outbreak, various efforts are undertaken to develop a quick, easy, inexpensive, and accurate way for diagnosis. Although many commercial diagnostic kits are available, detailed scientific evaluation is lacking, making the public vulnerable to fear of false-positive results. Moreover, current tissue sampling method from respiratory tract requires personal contact of medical staff with a potential asymptomatic SARSCOV-2 carrier and calls for safe and less invasive sampling method. Here, we have developed a convenient detection protocol for SARS-COV-2 based on a non-invasive saliva self-sampling method by extending our previous studies on development of a laboratory-safe and low-cost detection protocol based on qRT-PCR. We tested and compared various self-sampling methods of self-pharyngeal swab and self-saliva sampling from non-carrier volunteers. We found that the self-saliva sampling procedure gave expected negative results from all of the non-carrier volunteers within 2 hours, indicating cost-effectiveness, speed and reliability of the saliva-based method. For an automated assessment of the sampling quality and degree of positivity for COVID-19, we developed scalable formulae based on a logistic classification model using both cycle threshold and melting temperature from the qRT-PCR results. Our newly developed protocol will allow easy sampling and spatial-separation between patient and experimenter for guaranteed safety. Furthermore, our newly established risk assessment formula can be applied to a large-scale diagnosis in health institutions and agencies around the world.

Is cervical swab an efficient method for developing a new noninvasive prenatal diagnostic test for numerical and structural chromosome anomalies?

Background/aim: Prenatal diagnosis is vital to obtain healthy generation for risky pregnancies. There have been several approaches, some of which are routinely applied in clinics to evaluate the possible prenatal deficiencies and/or diseases. In the present study, we aimed to isolate the fetal cells from endocervical samples and try to identify possible anomalies which were proved by Amniocentesis (AS) and chorionic villus sampling (CVS) methods. Materials and methods: Endoservical specimens were collected from 100 pregnant women. Cells were separated in parallel by fluorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) using human leukocyte antigen (HLA) G233 and placental alkaline phosphatase (PLAP) antibodies. CMA (comprehensive meta-analysis) were carried out and male fetuses were confirmed with Sex determining region Y (SRY) amplification. Results: The percent of HLA G233 and placental and placental alkaline phosphatase (PLAP) positive cells were 4.55% and 84.59%, respectively. The percent of cells positive for both markers was 14.75%. CMA analyses were not informative. (SRY) was amplified in 67% of the samples. Conclusion: However, the success rate of the both cell sorting and scanning of DNA anomalies by aCGH and/or RT-PCR was limited, preventing the applicability of this proposal in the clinics. Still, the success of the proposed method depends on the development of the novel fetal cell-specific antibodies and the improvements in the sorting systems.

15-LOX-1 has diverse roles in the resensitization of resistant cancer cell lines to doxorubicin.

Lipoxygenases (LOXs) are a family of enzymes that can oxygenate polyunsaturated fatty acids. As a member of the family, 15-lipoxygenase-1 (15-LOX-1) specifically metabolizes arachidonic acid and linoleic acid. 15-LOX-1 can affect physiological and pathophysiological events via regulation of the protein-lipid interactome, alterations in intracellular redox state and production of lipid metabolites that are involved in the induction and resolution of inflammation. Although several studies have shown that 15-LOX-1 has an antitumorigenic role in many different cancer models, including breast cancer, the role of the protein in cancer drug resistance has not been established yet. In this study, we, for the first time, aimed to show the potential role of 15-LOX-1 in acquired doxorubicin (DOX) resistance in MCF7 and HeLa cancer cell lines. Our results show that ALOX15 was transcriptionally downregulated in DOX-resistant cells compared with their drug-sensitive counterparts. Moreover, overexpression of ALOX15 in the drug-resistant cells resulted in resensitization of those cells to DOX in a cell-dependent manner. 15-LOX-1 expression could induce apoptosis by activating PPARγ and enhance the accumulation of DOX in drug-resistant MCF7 cells by altering cellular motility properties, and membrane dynamics. However, HeLa DOX cells did not show any of these effects but were susceptible to cell death when treated with 13(S)-HODE. These results underline the role and importance of 15-LOX-1 in cancer drug resistance, and points to novel mechanisms as a therapeutic approach to overcome cancer drug resistance.

Recent chemo-/biosensor and bioimaging studies based on indole-decorated BODIPYs.

BODIPY is an important fluorophores due to its enhanced photophysical and chemical properties including outstanding thermal/photochemical stability, intense absorption/emission profiles, high photoluminescence quantum yield, and small Stokes' shifts. In addition to BODIPY, indole and its derivatives have recently gained attention because of their structural properties and particularly biological importance, therefore these molecules have been widely used in sensing and biosensing applications. Here, we focus on recent studies that reported the incorporation of indole-based BODIPY molecules as reporter molecules in sensing systems. We highlight the rationale for developing such systems and evaluate detection limits of the developed sensing platforms. Furthermore, we also review the application of indole-based BODIPY molecules in bioimaging studies. This article includes the evaluation of indole-based BODIPYs from synthesis to characterization and a comparison of the advantages and disadvantages of developed reporter systems, making it instructive for researchers in various disciplines for the design and development of similar systems.

Novel ruthenium(ii) and iridium(iii) BODIPY dyes: insights into their application in photodynamic therapy in vitro.

Organic-metal complexes are promising molecules for use in photodynamic therapy (PDT). The aim of this study was to investigate in vitro effects of novel Ru(ii) and Ir(iii) BODIPY complexes for PDT. These hybrid organic-metal molecules (Ru-BD and Ir-BD) have been synthesized via reactions of a BODIPY precursor (BD) with a phenanthroline unit bearing Ru(ii) (3) and novel Ir(iii) (4) compounds. The crystal structures of the new distyryl BODIPY (BD) and Ru(ii) complex (3) are also reported. The photophysical and singlet oxygen generation properties of Ru-BD and Ir-BD were investigated in comparison with unsubstituted BODIPY (BD). Moreover, Ru-BD and Ir-BD have been biologically evaluated in vitro in chronic myeloid leukemia and cervical cancer cell lines in terms of photodynamic therapy efficacy in the presence of BD control. These complexes were not toxic in the dark but red light was needed to induce cell death. These data support the fact that Ru-BD could be accepted as a valuable photosensitizer-drug for further PDT treatment.

Azaindole-BODIPYs: Synthesis, fluorescent recognition of hydrogen sulfate anion and biological evaluation.

The synthesized and sensing capability of two novel azaindole substituted mono and distyryl BODIPY dyes against bisulfate anion were reported. Structural characterizations of the targeted compounds were conducted by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 1H and 13C NMR spectroscopies. Photophysical properties of the azaindole substituted BODIPY compounds were investigated employing absorption and fluorescence spectroscopies in acetonitrile solution. It was found that the final compounds 3 and 4 exhibited exclusively selective and sensitive turn-off sensor behavior on HSO4- anion. Additionally, the stoichiometry ratio of the targeted compounds to bisulfate anion was measured 0.5 by Job's method. Also, density function theory was performed to the optical response of the sensor for targeted compounds. Furthermore, the cytotoxicity of Azaindole-BODIPYs was examined against living human leukemia K562 cell lines.

Dual function of programmed cell death 10 (PDCD10) in drug resistance.

Drug resistance, a major challenge in cancer chemotherapy, is a result of several mechanistic alterations including resistance to apoptosis. Apoptosis is a well-controlled cell death mechanism which is regulated by several signaling pathways. Alterations in structure, function, and expression pattern of the proteins involved in the regulation of apoptosis have been linked to drug resistance. Programmed Cell Death 10 (PDCD10) protein is recently associated with the regulation of cell survival and apoptosis. However, the role of PDCD10 in drug resistance has not been clearly established. Here, we aimed to figure out the role of PDCD10 in resistance to anti-cancer agents in different cell lines. We found that PDCD10 expression was cell- and anti-cancer agent-specific; down-regulated in doxorubicin- and docetaxel-resistant MCF7 cells while up-regulated in doxorubicin-resistant HeLa cells. Down-regulation of PDCD10 expression by siRNA in parental MCF7 cells increased the resistance while it increased sensitivity in doxorubicin-resistant HeLa cells. Similarly, over-expression of PDCD10 in parental HeLa cells increased the resistance to doxorubicin while it re-sensitized doxorubicin-resistant MCF7 cells. Moreover, the alterations in PDCD10 expression led to changes in caspase 3/7 activity and the levels of apoptosis-related genes. Our results point out a possible dual role of PDCD10 in drug resistance for the first time in the literature and emphasize PDCD10 as a novel target for reversal of drug resistance in cancer.

Iron metabolism and drug resistance in cancer.

Iron is an essential inorganic element for various cellular events. It is directly associated with cell proliferation and growth; therefore, it is expected that iron metabolism is altered in tumor cells which usually have rapid growth rates. The studies on iron metabolism of tumor cells have shown that tumor cells necessitated higher concentrations of iron and the genes of iron uptake proteins were highly over-expressed. However, there are limited number of studies on overall iron metabolism in drug-resistant tumor cells. In this article, we evaluated the studies reporting the relationship between drug resistance and iron metabolism and the utilization of this knowledge for the reversal of drug resistance. Also, the studies on iron-related cell death mechanism, ferroptosis, and its relation to drug resistance were reviewed. We focus on the importance of iron metabolism in drug-resistant cancer cells and how alterations in iron metabolism participate in drug-resistant phenotype.

Resistance to anticancer drugs permanently alters electrophoretic mobility of cancer cell lines.

Electrophoretic mobility is a physical phenomenon defining the mobility of charged particles in a solution under applied electric field. As charged biological systems, living cells including both prokaryotes and eukaryotes have been assessed in terms of electrophoretic mobility to decipher their electrochemical structure. Moreover, determination of electrophoretic mobility of living cancer cells have promoted the advance exploration of the nature of the cancer cells and separation of cancer cells from normal ones under applied electric field. However, electrophoretic mobility of drug-resistant cells has not yet been examined. In the present study, we determined the electrophoretic mobility of drug-resistant cancer cell lines for both suspension and adherent cells and compared with those of drug-sensitive counterparts. We showed that resistance to anticancer drugs alters the electrophoretic mobility in a permanent manner, even lasting without any exposure to anticancer agents for a long time period. We also studied the cellular morphologies of adherent cells where the cellular invaginations and protrusions were increased in drug-resistant adherent cells, which could be direct cause of altered surface charge and electrophoretic mobility as a result. These findings could be helpful in terms of understanding the electrophysiological and physicochemical background of drug resistance in cancer cells and developing systems to separate drug-sensitive cells from drug-resistant ones.

Modulation of Estrogen Response Element-Driven Gene Expressions and Cellular Proliferation with Polar Directions by Designer Transcription Regulators.

Estrogen receptor α (ERα), as a ligand-dependent transcription factor, mediates 17ß-estradiol (E2) effects. ERα is a modular protein containing a DNA binding domain (DBD) and transcription activation domains (AD) located at the amino- and carboxyl-termini. The interaction of the E2-activated ERα dimer with estrogen response elements (EREs) of genes constitutes the initial step in the ERE-dependent signaling pathway necessary for alterations of cellular features. We previously constructed monomeric transcription activators, or monotransactivators, assembled from an engineered ERE-binding module (EBM) using the ERα-DBD and constitutively active ADs from other transcription factors. Monotransactivators modulated cell proliferation by activating and repressing ERE-driven gene expressions that simulate responses observed with E2-ERα. We reasoned here that integration of potent heterologous repression domains (RDs) into EBM could generate monotransrepressors that alter ERE-bearing gene expressions and cellular proliferation in directions opposite to those observed with E2-ERα or monotransactivators. Consistent with this, monotransrepressors suppressed reporter gene expressions that emulate the ERE-dependent signaling pathway. Moreover, a model monotransrepressor regulated DNA synthesis, cell cycle progression and proliferation of recombinant adenovirus infected ER-negative cells through decreasing as well as increasing gene expressions with polar directions compared with E2-ERα or monotransactivator. Our results indicate that an 'activator' or a 'repressor' possesses both transcription activating/enhancing and repressing/decreasing abilities within a chromatin context. Offering a protein engineering platform to alter signal pathway-specific gene expressions and cell growth, our approach could also be used for the development of tools for epigenetic modifications and for clinical interventions wherein multigenic de-regulations are an issue.