O-GlcNAc modification of Sp1 inhibits the functional interaction between Sp1 and Oct1

Sp1 is a ubiquitous transcription factor that is modified by multiple O-linked N-acetylglucosamines (O-GlcNAc). Previously, O-GlcNAcylation of a specific site of Sp1 was shown to inhibit Sp1 transcriptional activity. Yet, how O-GlcNAc on other modification sites affects Sp1 function and how O-GlcNAcylation of Sp1 affects the transcriptional regulation of a target gene remains unknown. Here we show that O-GlcNAc within the second serine/threonine-rich region of Sp1 interrupts a known interaction between Sp1 and Oct1, and inhibits the cooperative activation of the U2 snRNA gene by Sp1 and Oct1.Structured summaryMINT-6803452: Sp1 (uniprotkb-P08047) physically interacts (MI:0218) with Oct1 (uniprotkb:P14859) by anti tag coimmunoprecipitation (MI:0007)MINT-6803426, MINT-6803438: Oct1 (uniprotkb:P14859) binds (MI:0407) to Sp1 (uniprotkb:P08047) by pull down (MI:0096)MINT-6803470, MINT-6803484: Sp1 (uniprotkb:P08047) physically interacts (MI:0218) with Oct1 (uniprotkb:P14859) by anti bait coimmunoprecipitation (MI:0006)