Presentation description

YY1 (Ying-Yang 1) is a crucial transcription factor in the body that regulates the expression of tumor suppressors and oncogenes. Thus, the study of its mechanisms contributes crucial information concerning oncogenic activity in cells. Results from the Sui lab show that deletion of the poly-His site removes YY1's ability to phase separate and function properly. Building on these findings, we further explored YY1 by studying the effect of ADP-ribosylation (ADPr) of its poly-His amino site. The experimental model in the lab involved creating bacterial and mammalian plasmids that coded for SIRT6 and its substrate, YY1, via polymerase chain reaction, and then transfecting mammalian cells with these plasmids. We also aimed to provide additional evidence demonstrating ADPr specifically at the histidine amino acid site through mass spectrometry analysis of NUDT16-mediated de-ADPr of a known SIRT6 poly-His substrate (MECP2). Results from mass spectrometry support that ADPr can occur on histidine, but require additional validation from the NUDT16 experiment. This will expand our scope of understanding of YY1's possible mechanisms. Phase-separation was observed in YY1-expressing mammalian cells. However, the association between SIRT6 and YY1 phase-separation yields inconclusive results; thus, further tests will be performed to elucidate this topic of discussion.