Two ZNF509 (ZBTB49) isoforms induce cell-cycle arrest by activating transcription of p21/CDKN1A and RB upon exposure to genotoxic stress.
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Jeon BN, Kim MK, Yoon JH, Kim MY, An H, Noh HJ, Choi WI, Koh DI, Hur MW
Two ZNF509 (ZBTB49) isoforms induce cell-cycle arrest by activating transcription of p21/CDKN1A and RB upon exposure to genotoxic stress.
Nucleic Acids Res. 2014 Oct;42(18):11447-61. doi: 10.1093/nar/gku857. Epub 2014 Sep 22.
- PubMed ID
- 25245946 [ View in PubMed]
- Abstract
ZNF509 is unique among POK family proteins in that four isoforms are generated by alternative splicing. Short ZNF509 (ZNF509S1, -S2 and -S3) isoforms contain one or two out of the seven zinc-fingers contained in long ZNF509 (ZNF509L). Here, we investigated the functions of ZNF509 isoforms in response to DNA damage, showing isoforms to be induced by p53. Intriguingly, to inhibit proliferation of HCT116 and HEK293 cells, we found that ZNF509L activates p21/CDKN1A transcription, while ZNF509S1 induces RB. ZNF509L binds to the p21/CDKN1A promoter either alone or by interacting with MIZ-1 to recruit the co-activator p300 to activate p21/CDKN1A transcription. In contrast, ZNF509S1 binds to the distal RB promoter to interact and interfere with the MIZF repressor, resulting in derepression and transcription of RB. Immunohistochemical analysis revealed that ZNF509 is highly expressed in normal epithelial cells, but was completely repressed in tumor tissues of the colon, lung and skin, indicating a possible role as a tumor suppressor.