Exploring novel piRNA-PIWI-interacting proteins and their function in gene silencing and cell differentiation

Yuguan Jiang
MSc Student 
Department of Biochemistry

Date: February 3, 2025
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Abstract:

PIWI-interacting RNAs (piRNAs) are small non-coding RNAs of 24-31 nucleotides in length. piRNAs are crucial for cellular activities in different animal species, and the PIWI family of proteins assist piRNAs in controlling gene expression both at the transcriptional and the post-transcriptional levels. The roles of piRNAs and PIWI proteins in the animal germ line have been widely studied, but their functions in somatic tissues, especially in somatic/adult stem cells, remain to be explored. MIWI is a known PIWI homologue in mice, and it is highly expressed in mouse embryonic stem cells (mESCs), along with the piRNA, piR-mmu-1499894. This led us to hypothesize that the piRNA-MIWI complex is important for cellular functions of mESCs and play a role in regulating the expression of genes responsible for their unique characteristics. To test the hypothesis, in our study, we employed immunoprecipitation, RNA-based pulldowns and mass spectrometry to identify proteins that interact with the piRNA-MIWI complex, with implications in target gene silencing. Our analysis discovered 11 potential candidates with known roles in RNA metabolism and cell differentiation. Upon further validation, we chose to investigate the protein RENT2, and observed that MIWI controls the expression of RENT2 and multiple pluripotent markers. In the future, we aim to uncover the mechanisms by which MIWI controls the expression of RENT2 and whether this relation alters the outcome of piRNA-guided gene silencing in stem cell pluripotency and differentiation. We expect that finding from our study will help uncover the non-canonical roles of the piRNA machinery, beyond the germ line, in animal development.