SRSF3 Is a Critical Requirement for Inclusion of Exon 3 of BIS Pre-mRNA.

Kyunghyun Yoo,Hye-Hyeon Yun,Jeong-Hwa Lee,Ji-Ye Baek,Jeehan Lee,Soon-Young Jung

doi:10.3390/cells9102325

Abstract

BCL-2 interacting cell death suppressor (BIS), also known as BAG3, is a multifunctional protein. Aberrant expression and mutation of BIS have been implicated in cancers and myopathy. However, there have only been a few studies on the splicing of BIS pre-mRNA. In the present study, through RT-PCR and sequencing in various cell lines and mouse tissues, we identified for the first time the presence of BIS mRNA isomers in which exon 3 or exons 2–3 are skipped. We also demonstrated that the depletion of SRSF3 promoted the skipping of exon 3 of BIS pre-mRNA in endogenous BIS and the GFP-BIS minigene. SRSF3 specifically interacts with the putative binding sites in exon 3, in which deletion promoted the skipping of exon 3 in the GFP-BIS minigene, which was comparable to the effect of SRSF knockdown. Even though acceleration of exon 3 skipping was not observed in response to various stimuli, SRSF3 depletion, accompanied by the production of a truncated BIS protein, inhibited the nuclear translocation of HSF1, which was restored by the wild-type BIS, not by exon 3-depleted BIS. Therefore, our results suggested that the maintenance of SRSF3 levels and subsequent preservation of the intact BIS protein is an important factor in modulating HSF1 localization upon cellular stress.

Highlights

BCL-2 interacting cell death suppressor (BIS), known as BAG3, is a 75-kDa protein that has several distinct domains, such as a BAG domain, a WW domain, a proline-rich repeat, and two conserved IPV (Ile-Pro-Val) motifs [1,2]
In order to define the physiological significance of BIS depleted in exon 3 (BIS-∆exon 3 (E3)), we examined the changes in the expression pattern of mRNA and protein of BIS during various cellular processes
In the present study, using PCR and sequencing in various cell lines, we identified for the first time the presence of alternatively spliced forms of BIS mRNA in which exon 3 or exons 2–3 are skipped

Summary

Introduction

BCL-2 interacting cell death suppressor (BIS), known as BAG3, is a 75-kDa protein that has several distinct domains, such as a BAG domain, a WW domain, a proline-rich repeat, and two conserved IPV (Ile-Pro-Val) motifs [1,2]. Through these distinct domains, BIS interacts with different molecular partners, which might underlie the diverse biological function of BIS, including modulation of apoptosis, autophagy, stress response, migration, invasion, as well as cytoskeleton organization [3,4]. FGF-2-driven BIS expression is mediated by Egr-1, while serum deprivation downregulates BIS via the reduction of c-Jun at

Methods

Results

Conclusion