ZSCAN4 is negatively regulated by the ubiquitin-proteasome system and the E3 ubiquitin ligase RNF20
JournalBiochemical and Biophysical Research Communications
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AbstractZscan4 is an early embryonic gene cluster expressed in mouse embryonic stem and induced pluripotent stem cells where it plays critical roles in genomic stability, telomere maintenance, and pluripotency. Zscan4 expression is transient, and characterized by infrequent high expression peaks that are quickly down-regulated, suggesting its expression is tightly controlled. However, little is known about the protein degradation pathway responsible for regulating the human ZSCAN4 protein levels. In this study we determine for the first time the ZSCAN4 protein half-life and degradation pathway, including key factors involved in the process, responsible for the regulation of ZSCAN4 stability. We demonstrate lysine 48 specific polyubiquitination and subsequent proteasome dependent degradation of ZSCAN4, which may explain how this key factor is efficiently cleared from the cells. Importantly, our data indicate an interaction between ZSCAN4 and the E3 ubiquitin ligase RNF20. Moreover, our results show that RNF20 depletion by gene knockdown does not affect ZSCAN4 transcription levels, but instead results in increased ZSCAN4 protein levels. Further, RNF20 depletion stabilizes the ZSCAN4 protein half-life, suggesting that RNF20 negatively regulates ZSCAN4 stability. Due to the significant cellular functions of ZSCAN4, our results have important implications in telomere regulation, stem cell biology, and cancer. Copyright 2018 The Authors
SponsorsThis work was supported in part by the Maryland Stem Cell Research Fund (MSCRF) grant 2013-MSCRFII-0165 and the National Institutes of Health/ NINDS grant 1R21 NS095088-01A1 (MZ). We thank the Weitzman family for their contribution and support of this work. RK was partially supported by the MSCRF grant 2014-MSCRF-0719.
Identifier to cite or link to this itemhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85042650302&doi=10.1016%2fj.bbrc.2018.02.155&partnerID=40&md5=a3788e064d86391cbfe9dc2268c2cb38; http://hdl.handle.net/10713/9090