RNF4 regulates zebrafish granulopoiesis through the DNMT1‐C/EBPα axis

Abstract

RING finger protein 4 (RNF4) is a multifunctional small ubiquitin-related modifier (SUMO)-targeted ubiquitin E3 ligase (STUbL) ubiquitously expressed in all tissues, and which mainly participates in DNA repair and in chromatin and transcriptional regulation. Although RNF4 has been implicated in hematopoietic disorders, its ontogenic role during hematopoietic development remains undiscovered. We generated a zebrafish rnf4 knockout line by using transcription activator-like effector nucleases technology to address the impact of rnf4 during hematopoiesis. Rnf4-deficient zebrafish embryos exhibited sharply decreased neutrophils numbers during both primitive and definitive hematopoiesis. Mechanistic studies revealed that repression of the key granulocytic activator, CCAAT/enhancer-binding protein α ( c/ebpα), via promoter hypermethylation by SUMOylated DNA methyltransferase 1 (DNMT1) was the main cause of impaired granulopoiesis in rnf4-deficient zebrafish. In addition, for the first time, we identified DNMT1 as a potential new STUbL substrate of RNF4, with knockdown of dnmt1 largely restoring primitive and definitive granulopoiesis in rnf4-deficient zebrafish. Collectively, RNF4 is indispensable for zebrafish granulopoiesis through regulation of the DNMT1-C/EBPα functional axis.-Wang, L., Liu, X., Wang, H., Yuan, H., Chen, S., Chen, Z., de The, H., Zhou, J., Zhu, J. RNF4 regulates zebrafish granulopoiesis through the DNMT1-C/EBPα axis.

RNF4—A Paradigm for SUMOylation‐Mediated Ubiquitination

“…Wang and colleagues recently reported a role of RNF4 in the regulation of zebrafish granulopoiesis through the DNMT1‐C/EBPa axis . In that study, the authors found DNMT1 as a potential new substrate of RNF4.…”

Zebrafish: a convenient tool for myelopoiesis research

“…The neutrophils were largely decreased in rnf4-deficient zebrafish larvae during both primitive and definitive myelopoiesis. Mechanistically, the hypermethylation of c/ebpα promoter by SUMOylated DNA methyltransferase 1 (DNMT1) led to granulopoiesis defect in rnf4-deficient zebrafish (Wang et al 2018a ). Besides DNMT1, another methyltransferase, smyd5, suppresses the excessive expressions of primitive and definitive myelopoietic genes, such as pu.1 , mpx , l-plastin , and c-myb (Fujii et al 2016 ).…”

Unraveling DNA Repair Processes In Vivo: Insights from Zebrafish Studies

“…One gene of interest is the small ubiquitin-related modifier (SUMO)-targeted E3 ligase, RNF4. RNF4 is primarily involved in DNA damage repair and chromatin regulation, contributing significantly to maintaining genomic integrity and the loss of rnf4 results in defects in embryonic myeloid development in zebrafish [72]. RNF4 regulates granulopoiesis via the regulation of DNA methyltransferase 1 (DNMT1) and the CCAAT/enhancer-binding protein α (C/EBPα) axis.…”