Alternative Splicing of chrng gene generates Novel Isoforms with different N‐terminals

Abstract

The γ‐subunit of nicotinic acetylcholine receptor is encoded by chrng gene of mouse genome. It plays an important role in maturation of the receptor. The gene contains 12 exons and 11 introns. Two transcripts of chrng have already been reported that arise due to the presence or absence of 5th exon. The aim of this study is to analyze the gene structure and identify any other transcript that may produce different isoforms.A combination of bioinformatics tools like gene finders, blast searches, alignment tools, etc. were used to study chrng gene. Using these methods three new coding exons namely N1, N2, and N3 were identified from 5′ UTR and 1st intron of chrng. Each one of these is capable of alternatively replacing the 1st exon of the reported transcript making three new transcripts differing at the 5′ end. Est database searches also revealed the presence of an Est corresponding to N3 exon. To confirm the presence of these transcripts RT‐PCR followed by semi‐nested PCR of RNA isolated from mouse brain was performed. Sequencing of the products further confirmed the results.Thus, using bioinformatics and molecular biology techniques we have identified three new transcripts of chrng encoding γ‐subunit and having different N‐terminal sequences. The sequence encoded by N3 exon is predicted to have a signal peptide, phosphorylation and glycosylation site which lack in all other isoforms. Funding from CSIR, India is acknowledged.