Use of combined in silico expression data and phylogenetic analysis to identify new oocyte genes encoding RNA binding proteins in the mouse

Abstract

During folliculogenesis, oocytes accumulate maternal mRNAs in preparation for the first steps of early embryogenesis. The processing of oocyte mRNAs is ensured by heterogeneous nuclear ribonucleoproteins (hnRNPs) genes that encode RNA binding proteins implied in mRNA biogenesis, translation, alternative splicing, nuclear exportation, and degradation. In the present work, by combining phylogenetic analyses and, when available, in silico expression data, we have identified three new oocyte-expressed genes encoding RNA binding proteins by using two strategies. Firstly, we have identified mouse orthologs of the Car1 gene, known to be involved in regulation of germ cell apoptosis in C. elegans, and of the Squid gene, required for the establishment of anteroposterior polarity in the Drosophila oocyte. Secondly, we have identified, among genes whose ESTs are highly represented in oocyte libraries, a paralog of Poly(A) binding protein--Interacting Protein 2 (Paip2) gene, known to inhibit the interaction of the Poly(A)-Binding Protein with Poly(A) tails of mRNAs. For all of these genes, the expression in oocyte was verified by in situ hybridization. Overall, this work underlines the efficiency of in silico methodologies to identify new genes involved in biological processes such as oogenesis.

Genes Involved in Drosophila melanogaster Ovarian Function Are Highly Conserved Throughout Evolution

“…2000 ). Several mechanisms contributing to this translational control, including conserved RNA-binding proteins that control translation by 3′ UTR binding and the assembly of mRNA–protein complexes called mRNPs, have been investigated not only in invertebrates but also in vertebrates ( Drouilhet et al. 2008 ; Boateng et al.…”

“…2012 ). We have previously identified genes encoding mRNA binding proteins that are highly expressed in the mouse oocyte, based on their phylogenetic relationship with fruit flies and nematode orthologs known to be involved in oogenesis in both species ( Drouilhet et al. 2008 ).…”

A Comparative Analysis of Oocyte Development in Mammals

“…Cells 2020, 9, x 4 of 26 of these mouse orthologs are expressed exclusively or most preferentially in the oocyte as compared to other cells [38]. Beyond meiosis, several functions such as mRNA binding seem to be highly conserved in oocytes from nonvertebrates to vertebrates [38,39]. This is not unexpected, given the prominent role of posttranscriptional control of gene expression, as seen in §2.2.…”

Paip2 cooperates with Cbp80 at an active promoter and participates in RNA Polymerase II phosphorylation in Drosophila

“…In mammals, Paip2 proteins have important functions in spermatogenesis, oogenesis, and in the functioning of the nervous system. Paip2a is expressed in late spermatids, while its paralogue Paip2b shows stronger expression in oocytes . Paip2a‐knockout mice are male sterile, indicating an important role for this protein as a translational regulator during sperm maturation .…”