Relative strength of 5’ splice-site strength defines functions of SRSF2 and SRSF6 in alternative splicing of Bcl-x pre-mRNA

• Published in: BMB reports 2021, 54(3), , pp.176-181
• Main Authors: Choi, Namjeong, Liu, Yongchao, Oh, Jagyeong, Ha, Jiyeon, Ghigna, Claudia, Zheng, Xuexiu, Shen, Haihong
• Format: Article
• Language: English
• Subjects: 화학
• ISSN: 1976-6696; 1976-670X
• DOI: 10.5483/BMBRep.2021.54.3.170

Bcl-x, a member of the Bcl-2 family, plays a key role in apoptosis. Alternative splicing of Bcl-x pre-mRNA through alternative 5’ splice-site selection produces an anti-apoptotic mRNA isoform that includes exon 2b and a pro-apoptotic Bcl-x mRNA isoform that excludes exon 2b. Here we used Bcl-x minigene and identified SRSF2 and SRSF6 as two regulatory factors of 5’ splice-site selection of Bcl-x pre-mRNA. We selected binding clusters closer to 5’ splice-sites from multiple potential binding sites of SRSF2 and SRSF6 to perform loss of functions analysis through site-directed mutagenesis. Our results demonstrated that these mutations did not abolish regulatory functions of SRSF2 or SRSF6, indicating that a single binding motif or a cluster was not a functional target of these proteins in Bcl-x pre-mRNA splicing. Random deletion mutagenesis did not disrupt the role of SRSF2 and SRSF6. Importantly, mutagenesis of 5’ splice-site to a conserved or a weaker score demonstrated that the weaker strength of the target 5’ splice-site or higher strength of the other 5’ splice-site strength limited the role of SRSF2 and SRSF6 in 5’ splice-site activation.