Identification and expression of alternatively spliced novel isoforms of cancer associated MYD88 lacking death domain in mouse.

MYD88 is an adaptor protein known to involve in activation of NF-κB through IL-1 receptor and TLR stimulation. It consists of N-terminal death domain and C-terminal Toll/IL-R homology domain that mediates its interaction with IL-1R associated kinase and IL-1R/TLR, respectively. MYD88 contributes to various types of carcinogenesis due to its involvement in oncogene induced inflammation. In the present study, we have recognized two new alternatively spliced variants of MyD88 gene in mouse using bioinformatics tools and molecular biology techniques in combination. The newly identified non-coding exon (NE-1) from 5' upstream region alternatively splices with either exon E-2 or exon E-5 to produce two novel transcript variants MyD88N1 and MyD88N2 respectively. The transcript variant MyD88N1 was expressed in several tissues studied while the variant MyD88N2 was found to be expressed only in the brain. The analysis of the upstream region of novel exon by in silico approach revealed new promoter region PN, which possess potential signature sequences for diverse transcription factors, suggesting complex gene regulation. Studies of post translational modifications of conceptualized amino acid sequences of these isoforms revealed diversity in properties. Western blot analysis further confirmed the expression of protein isoform MYD88N1.