Project description:Diverse sex determination mechanisms have been reported in eukaryotes, but little is known about the genetic pathways leading to sex determination in red algae. Sex-specific genes that could be involved in sex determination and sexual differentiation were investigated in a red alga Bostrychia moritziana by analyzing the transcriptomes of various phases including males, females and tetrasporophytes. Sex-dominantly-expressed genes which shows >10 fold difference between sexes were isolated using comparative RNA-seq analysis. We found 19 gene homologues, 10 from males and 9 from females, that were found only in one sex in genomic amplification. This suggests that these divergent homologues are on non-recombining, possibly different, chromosomes in their respective sexes. Most of the sex-specific genes are involved in important cellular processes including chromosome segregation, nucleo-cytoplasmic protein shuttling or tRNA modification. Quantitative PCR analysis also showed that some sex-specific genes were differently regulated during critical events of sexual reproduction like fertilization and carposporophyte development. We could also localize the expression of a male-specific gene in spermatia before and after gamete binding using RNA in situ hybridization. Another set of transcripts were found that were sex-dominantly-expressed, but not sex-specific. 19 out of 39 sex-dominantly-expressed transcripts were annotated to transposable elements, but none of them was sex-specific. Our results suggest that sexual differentiation in B. moritziana may be achieved by multi-level regulation of cellular processes, both from genes present only in one sex and differential expression of shared genes.
Project description:This study aims to investigate the DNA methylation patterns at transcription factor binding regions and their evolutionary conservation with respect to binding activity divergence. We combined newly generated bisulfite-sequencing experiments in livers of five mammals (human, macaque, mouse, rat and dog) and matched publicly available ChIP-sequencing data for five transcription factors (CEBPA, HNF4a, CTCF, ONECUT1 and FOXA1). To study the chromatin contexts of TF binding subjected to distinct evolutionary pressures, we integrated publicly available active promoter, active enhancer and primed enhancer calls determined by profiling genome wide patterns of H3K27ac, H3K4me3 and H3K4me1.
