NGS analysis of RNAs associated with the betaNACtes-containing ribosomes in Drosophila melanogaster testes

NAC (nascent polypeptide-associated complex) post-meiotic heterodimeric aß-complex promoting chaperone-like cotranslational protein folding on the ribosome and its early role in the birth of nascent proteins is suggested. Here, we demonstrate the presence of specific NAC complex (NACtes) associated with ribosomes in spermatocytes. The RNAseq analysis of mRNAs associated with testis-specific and immunoprecipitated NACtes-carrying ribosomes revealed a preferential association of the latter with mRNAs encoding meiotic and post meiotic proteins. The NACtes ribosomes are also shown to be enriched in mRNAs encoding proteins of central metabolism pathways that have been reported as overexpressed in testes. The specificity of association of NACtes ribosomes with particular mRNA sets was also demonstrated by the observation of significant underrepresentation of abundant mRNAs encoding ubiquitously expressed ribosomal proteins in NACtes-associated ribosomes. At the same time, NACtes ribosomes are enriched in mRNA encoding a testis specific ribosomal protein. These results bring new arguments in favor of “specialized ribosomes hypothesis” proposing a special composition of ribosomes necessary for the control of selected gene expression. Overall design: RNA profiles from the fraction of testes ribosomes immunoprecipitated with ßNACtes antibodies (three replicas) and from total testes ribosomes (two replicas)