Acetylation-Mimic Mutation of TRIM28-Lys304 to Gln Attenuates the Interaction with KRAB-Zinc-Finger Proteins and Affects Gene Expression in Leukemic K562 Cells

Abstract

TRIM28/KAP1/TIF1β is a crucial epigenetic modifier. Genetic ablation of trim28 is embryonic lethal, although RNAi-mediated knockdown in somatic cells yields viable cells. Reduction in TRIM28 abundance at the cellular or organismal level results in polyphenism. Posttranslational modifications such as phosphorylation and sumoylation have been shown to regulate TRIM28 activity. Moreover, several lysine residues of TRIM28 are subject to acetylation, but how acetylation of TRIM28 affects its functions remains poorly understood. Here, we report that, compared with wild-type TRIM28, the acetylation-mimic mutant TRIM28-K304Q has an altered interaction with Krüppel-associated box zinc-finger proteins (KRAB-ZNFs). The TRIM28-K304Q knock-in cells were created in K562 erythroleukemia cells by CRISPR-Cas9 (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein nuclease 9) gene editing method. Transcriptome analysis revealed that TRIM28-K304Q and TRIM28 knockout K562 cells had similar global gene expression profiles, yet the profiles differed considerably from wild-type K562 cells. The expression levels of embryonic-related globin gene and a platelet cell marker integrin-beta 3 were increased in TRIM28-K304Q mutant cells, indicating the induction of differentiation. In addition to the differentiation-related genes, many zinc-finger-proteins genes and imprinting genes were activated in TRIM28-K304Q cells; they were inhibited by wild-type TRIM28 via binding with KRAB-ZNFs. These results suggest that acetylation/deacetylation of K304 in TRIM28 constitutes a switch for regulating its interaction with KRAB-ZNFs and alters the gene regulation as demonstrated by the acetylation mimic TRIM28-K304Q.

A retrospective case-control study for Clinical Validation of mutated ZNF208 as a novel biomarker of fatal blast crisis in Chronic Myeloid Leukemia

“…The engagement with dimeric Trim28 subsequently attracts the epigenetic apparatus to achieve strong transcriptional suppression [67][68][69]. As ZNF208 G64A mutation under our investigation also lies in KRAB domain of znf208 protein, it may have a role in KAP1-mediated repression of some other target proteins in the genome, leading to CML progression in our subset of CML patients and utilizing agonists of ZNFs and KP-1 can lead to development of novel anti-cancer drugs [69][70].…”

“…The engagement with dimeric Trim28 subsequently attracts the epigenetic apparatus to achieve strong transcriptional suppression [67-69]. As ZNF208 G64A mutation under our investigation also lies in KRAB domain of znf208 protein, it may have a role in KAP1-mediated repression of some other target proteins in the genome, leading to CML progression in our subset of CML patients and utilizing agonists of ZNFs and KP-1 can lead to development of novel anti-cancer drugs [69-70]. These studies show that by integrating multi-omics with artificial intelligence (AI), further studies can expedite the cancer drug development for treating the currently fatal phenotypes of cancers like blast-crisis CML [43-49.…”