Complex Genetic Interactions between Piwi and HP1a in the Repression of Transposable Elements and Tissue-Specific Genes in the Ovarian Germline

International Journal of Molecular Sciences

Nikolay Zenkin¹  Anastasia D. Stolyarenko²  Mikhail S. Klenov²  Artem A. Ilyin² 

[1] Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle Upon Tyne NE2 4AX, UK;Department of Molecular Genetics of the Cell, Institute of Molecular Genetics of National Research Centre «Kurchatov Institute», 2 Kurchatov Sq., 123182 Moscow, Russia;

关键词: HP1;    Piwi;    piRNA;    transposable elements;    germline;   

DOI  :  10.3390/ijms222413430

来源: DOAJ

【 摘 要 】

Insertions of transposable elements (TEs) in eukaryotic genomes are usually associated with repressive chromatin, which spreads to neighbouring genomic sequences. In ovaries of Drosophila melanogaster, the Piwi-piRNA pathway plays a key role in the transcriptional silencing of TEs considered to be exerted mostly through the establishment of H3K9me3 histone marks recruiting Heterochromatin Protein 1a (HP1a). Here, using RNA-seq, we investigated the expression of TEs and the adjacent genomic regions upon Piwi and HP1a germline knockdowns sharing a similar genetic background. We found that the depletion of Piwi and HP1a led to the derepression of only partially overlapping TE sets. Several TEs were silenced predominantly by HP1a, whereas the upregulation of some other TEs was more pronounced upon Piwi knockdown and, surprisingly, was diminished upon a Piwi/HP1a double-knockdown. We revealed that HP1a loss influenced the expression of thousands of protein-coding genes mostly not adjacent to TE insertions and, in particular, downregulated a putative transcriptional factor required for TE activation. Nevertheless, our results indicate that Piwi and HP1a cooperatively exert repressive effects on the transcription of euchromatic loci flanking the insertions of some Piwi-regulated TEs. We suggest that this mechanism controls the silencing of a small set of TE-adjacent tissue-specific genes, preventing their inappropriate expression in ovaries.

【 授权许可】

Unknown