Biology subjects

Birol, O.

Publications and source records attributed to Birol, O..

3 recordsLinked to original sources

bioRxiv2025

The Dream and MEC NuRD Complexes reinforce SPR-5/MET-2 maternal reprogramming to maintain the germline-soma distinction

The proper coordination of transcription factors, ATP dependent chromatin remodelers and histone modifications is essential for tissue specific gene expression, but how gene expression is regulated at these different levels is not well understood. In C. elegans, H3K4 methylation that is acquired in the germline is reprorgammed at fertilization by the H3K4me1/2 demethlyase SPR-5/LSD1/KDM1A and the H3K9 methyltransferase MET-2/SETDB1/KMT2E. SPR-5/MET-2 maternal reprogramming is required to help establish the germline-soma distinction and prevent developmental delay by preventing inherited H3K4 methylation from inappropriately maintaining germline gene expression in somatic tissues. To determine if the DREAM transcriptional repressor complex and the MEC NuRD ATP dependent nucleosome remodeling and histone deacetylase complex function to reinforce SPR-5/MET-2 maternal reprogamming, we asked if loss of these complexes affects the ectopic germline transcription and developmental delay in spr-5; met-2 double mutants. We find that knocking down the DREAM or MEC NuRD complexes specifically exacerbates the developmental delay and ectopic expression of germline genes in the soma caused by loss of SPR-5 and MET-2. In addition, the DREAM and MEC NuRD complexes bind together at SPR-5/MET-2 reprogramming targets. These data suggest that the transcriptional repression of DREAM and the ATP dependent chromatin remodeling and deactylation activities of the MEC NuRD complex are required somatically to reinforce maternal histone reporgamming by SPR-5/MET-2. Thus, these data provide a novel example of how gene regulation is coordinated at multiple levels to maintain the germline-soma distinction and ensure proper development.

genetics↗

bioRxiv2022

Cellular reprogramming with ATOH1, GFI1, and POU4F3 implicate epigenetic changes and cell-cell signaling as obstacles to hair cell regeneration in mature mammals

Reprogramming of the cochlea with hair cell-specific transcription factors such as ATOH1 has been proposed as a potential therapeutic strategy for hearing loss. ATOH1 expression in the developing cochlea can efficiently induce hair cell regeneration but the efficiency of hair cell reprogramming declines rapidly as the cochlea matures. We developed Cre-inducible mice to compare hair cell reprogramming with ATOH1 alone or in combination with two other hair cell transcription factors, GFI1 and POU4F3. In newborn mice, all transcription factor combinations tested produced large numbers of cells with the morphology of hair cells and rudimentary mechanotransduction properties. However, one week later, only a combination of ATOH1, GFI1 and POU4F3 could reprogram non-sensory cells of the cochlea to a hair cell fate, and these new cells were less mature than cells generated by reprogramming one week earlier. We used scRNA-seq and combined scRNA-seq and ATAC-seq to suggest at least two impediments to hair cell reprogramming in older animals. First, hair cell gene loci become less epigenetically accessible in non-sensory cells of the cochlea with increasing age. Second, signaling from hair cells to supporting cells, including Notch signaling, can prevent reprogramming of many supporting cells to hair cells, even with three hair cell transcription factors. Our results shed light on the molecular barriers that must be overcome to promote hair cell regeneration in the adult cochlea.

developmental biology↗

bioRxiv2017

A Resource For The Allele-Specific Analysis Of DNA Methylation At Multiple Genomically Imprinted Loci In Mice

Genomically imprinted loci are expressed mono-allelically dependent upon the parent of origin. Their regulation not only illuminates how chromatin regulates gene expression but also how chromatin can be reprogrammed every generation. Because of their distinct parent of origin regulation, analysis of imprinted loci can be difficult. Single nucleotide polymorphisms (SNPs) are required to accurately assess these elements allele-specifically. However, publicly available SNP databases lack robust verification, making analysis of imprinting difficult. In addition, the allele-specific imprinting assays that have been developed employ different mouse strains, making it difficult to systemically analyze these loci. Here, we have generated a resource that will allow the allele-specific analysis of many significant imprinted loci in a single hybrid strain of Mus musculus. This resource includes verification of SNPs present within ten of the most widely used imprinting control regions and allele-specific DNA methylation assays for each gene in a C57BL/6J and CAST/EiJ hybrid strain background.

genetics↗