573 / 2019-04-05 12:12:42

Characterization of an Arabidopsis splicing factor and its five transcript isoforms

Alternative splicing,Splicing factors

全体主题 > RNA Biology

Alternative splicing (AS) is a common type of post-transcriptional regulation in eukaryotes that allows one pre-mRNA be processed into multiple mRNA transcripts. As a result, protein isoforms encoded by the mRNA variants might be structurally and functionally different, due to the presence or absence of certain motifs. Besides, AS can regulate transcripts abundance by generating untranslated mRNA isoforms. However, although a large amount of the alternative transcripts have been detected in Arabidopsis, their biological roles largely remain unknown.

Serine/Arginine-rich (SR) proteins are a major family of splicing regulators required in AS. Interestingly, SR genes themselves are often transcribed into multiple transcript isoforms, which adds to the complexity of AS regulation. SR184 is an Arabidopsis SR gene that has at least seven transcript isoforms encoding five hypothetical proteins. The full-length SR184 is a multidomain protein and differed domain organizations exist among its five isoforms. Upon heat treatment, most SR184 mRNA isoforms showed different degrees of increase while SR184.2 remained unaffected. When transiently expressed in Arabidopsis protoplast, SR184.1, SR184.2 and SR184.3 showed nucleus localization while SR184.4 was distributed in punctate signals in cytoplasm. Different properties displayed by the SR184 isoforms at either mRNA or protein level suggested that some of them might possess distinct functions.