Common as well as unique methylation-sensitive DNA regulatory elements in three mammalian SLC9C1 genes.

The SLC9C1 gene (which encodes the NHE10 protein) is essential for male fertility in both mice and humans, however the epigenetic mechanisms regulating its testis/sperm-specific gene expression have yet to be studied. Here we identify and characterize DNA regulatory elements of the SLC9C1 gene across three mammalian species: mouse, rat, and human. First, in silico analysis of these mammalian SLC9C1 genes identified a CpG island located upstream of the transcription start site in the same relative position in all three genes. Further analysis reveals that this CpG island behaves differently, with respect to gene regulatory activity, in the mouse SLC9C1 gene than it does in the rat and human SLC9C1 gene. The mouse SLC9C1 CpG island displays strong promoter activity by itself and seems to have a stronger gene regulatory effect than either the rat or human SLC9C1 CpG islands. While the function of the upstream SLC9C1 CpG island may be divergent across the three studied species, it appears that the promoters of these three mammalian SLC9C1 genes share similar DNA methylation-sensitive regulatory mechanisms. All three SLC9C1 promoter regions are differentially methylated in lung and testis, being more hypermethylated in lung relative to the testis, and DNA sequence alignments provide strong evidence of primary sequence conservation. Luciferase assays reveal that in vitro methylation of constructs containing different elements of the three SLC9C1 genes largely exhibit methylation-sensitive promoter activity (reduced promoter activity when methylated) in both HEK 293 and GC-1spg cells. In total, our data suggest that the DNA methylation-sensitive elements of the mouse, rat, and human SLC9C1 promoters are largely conserved, while the upstream SLC9C1 CpG island common to all three species seems to perform a different function in mouse than it does in rat and human. This work provides evidence that while homologous genes can all be regulated by DNA methylation-dependent epigenetic mechanisms, the location of the specific cis-regulatory elements responsible for this regulation can differ across species.

Common as well as unique methylation-sensitive DNA regulatory elements in three mammalian SLC9C1 genes.

The SLC9C1 gene (which encodes the NHE10 protein) is essential for male fertility in both mice and humans, however the epigenetic mechanisms regulating its testis/sperm-specific gene expression have yet to be studied. Here we identify and characterize DNA regulatory elements of the SLC9C1 gene across three mammalian species: mouse, rat, and human. First, in silico analysis of these mammalian SLC9C1 genes identified a CpG island located upstream of the transcription start site in the same relative position in all three genes. Further analysis reveals that this CpG island behaves differently, with respect to gene regulatory activity, in the mouse SLC9C1 gene than it does in the rat and human SLC9C1 gene. The mouse SLC9C1 CpG island displays strong promoter activity by itself and seems to have a stronger gene regulatory effect than either the rat or human SLC9C1 CpG islands. While the function of the upstream SLC9C1 CpG island may be divergent across the three studied species, it appears that the promoters of these three mammalian SLC9C1 genes share similar DNA methylation-sensitive regulatory mechanisms. All three SLC9C1 promoter regions are differentially methylated in lung and testis, being more hypermethylated in lung relative to the testis, and DNA sequence alignments provide strong evidence of primary sequence conservation. Luciferase assays reveal that in vitro methylation of constructs containing different elements of the three SLC9C1 genes largely exhibit methylation-sensitive promoter activity (reduced promoter activity when methylated) in both HEK 293 and GC-1spg cells. In total, our data suggest that the DNA methylation-sensitive elements of the mouse, rat, and human SLC9C1 promoters are largely conserved, while the upstream SLC9C1 CpG island common to all three species seems to perform a different function in mouse than it does in rat and human. This work provides evidence that while homologous genes can all be regulated by DNA methylation-dependent epigenetic mechanisms, the location of the specific cis-regulatory elements responsible for this regulation can differ across species.

A Review of OB/GYN, Internal Medicine, Family Medicine, and Pediatrics Residency Program Websites for Diversity, Equity, and Inclusion Elements.

Background: Residency program websites have become a central source of information for applicants due to a shift toward virtual interviewing. Applicants, particularly those from diverse backgrounds, place strong value on programs that present commitments to diversity, equity, and inclusion (DEI). The DEI content of residency program websites for primary care specialties has been largely unexplored. Objective: The objective of this study is to review, in an exploratory manner, family medicine, internal medicine, obstetrics and gynecology, and pediatrics residency program websites for number of DEI elements present. By identifying lacking DEI content, we hope to give residency programs that are seeking to increase diversity among applicants some direction for improving their websites. Methods: We reviewed all available residency program websites (1814) in the Fellowship and Residency Electronic Interactive Database (FREIDA) from August to December 2021. Each website was evaluated for the presence of 10 DEI elements chosen from previously published website reviews and informal applicant surveys. Some elements included the presence of resident and faculty photos/biographies, patient population descriptions, and dedicated DEI curricula. Program demographic information was collected, and summative statistics were performed. Results: The average number of DEI elements displayed per program ranged from 3.5 (internal medicine) to 4.9 (pediatrics). The most common elements were resident and faculty photographs/biographies. Internal medicine programs displayed significantly fewer elements than the other 3 specialties. This difference remained significant after controlling for program size, location, and type. Conclusions: This study highlights a lack of DEI elements available for residency program website visitors to review.