HEXIM1-binding elements on mRNAs identified through transcriptomic SELEX and computational screening

作者：Fujimoto Yuki; Nakamura Yoshikazu; Ohuchi Shoji^*

来源：Biochimie, 2012, 94(9): 1900-1909.

DOI：10.1016/j.biochi.2012.05.003

• HEXIM1
• SELEX
• cad mRNA
• brd4 mRNA
• tcf3 mRNA

The positive transcription elongation factor b (P-TEFb) is one of the main regulatory factors of the transcription mediated by RNA polymerase II (RNAPII). P-TEFb promotes transcriptional elongation by phosphorylating its targets, which include the C-terminal domain of RNAPII. The activity of P-TEFb is negatively regulated by an RNA-binding protein HEXIM1 in association with 7SK snRNA. To search for other cellular RNAs that bind to HEXIM1, we used systematic evolution of ligands by exponential enrichment (SELEX) with the HeLa cDNA library as the initial pool source. We identified cad mRNA as a HEXIM1-binding RNA and confirmed their association in HeLa cells. In vitro mutational analysis showed that cad mRNA binds to HEXIM1 through its bulged stem structure located in exon 11. In addition, a computational search revealed other RNAs with similar stem structures, including brd4 and tcf3 mRNAs, both of which were shown to be coimmunoprecipitable with anti-HEXIM1 antibody in HeLa cells. Our findings suggest a possible role for HEXIM1 in the regulation of specific gene expressions.

• 出版日期2012-9
• 单位河北医科大学