Accepted_test

Overview of genes transcribed in the chicken lampbrush-stage oocyte and their key transcriptional regulators
by Anton Fedorov | Mikhail Schelkunov | Anna Fedotova | Alla Krasikova | Saint-Petersburg State University, Saint-Petersburg, Russia | Skolkovo Institute of Science and Technology | Skolkovo Institute of Science and Technology | Saint-Petersburg State University, Saint-Petersburg, Russia
Abstract ID: 468
Event: BGRS-abstracts
Sections: [Sym 1] Section “Genome-wide transcriptomics (differential gene expression)”

Recently, we performed nuclear and cytoplasmic transcriptome profiling of chicken oocytes at the lampbrush chromosome stage of oogenesis. Here we have undertaken a functional characterisation of the genes expressed in chicken oocytes, tracing their expression levels during early embryogenesis and predicting their transcriptional regulators. Genes expressed in the oocyte nucleus are characterised by a broader expression profile compared to genes whose transcripts were absent in the oocyte. Clusters of genes whose high transcript levels correlate with each other in the oocyte nucleus and cytoplasm are mainly associated with essential cellular processes including transcription, mRNA catabolism, piRNA metabolism, DNA repair, RNA splicing, protein synthesis, DNA replication, cell cycle progression and mitochondria functions. Enrichment analysis was used to find key transcription regulators from ChEA 2022 database, which are associated with subsets of genes with the highest and the lowest levels in chicken oocyte. Hypertranscription on lampbrush chromosomes can be activated by predicted transcriptional regulators MYC, YY1, E2F1, KDM5B, ZFX, and others. At the same time, repression of the inactived genes in avian lampbrush chromosomes can be controlled by epigenetic mechanisms involving Polycomb complexes PRC1 and PRC2. We assume that maternally deposited transcripts derived from the oocyte nucleus are required for the cellular processes associated with oogenesis and early embryogenesis.