Over 90% of human genes undergo alternative splicing, a form of messenger RNA processing that yields multiple proteins from a single gene, a paper published online in this week’s Nature suggests.
When the human genome was decoded there was a lower than expected number of genes, prompting renewed interest in alternative splicing. Therefore, Christopher Burge and colleagues analysed the entire mRNA content of 15 different tissue types or cancer cell lines to produce a comprehensive catalogue of gene and alternative mRNA expression. Almost all genes that have interruptions in their coding regions are alternatively spliced, they find ? a mechanism that permits greater phenotypic complexity than indicated by gene number alone.
Alternative splicing also seems to be linked to polyadenylation, a process whereby non-templated adenines are added to the ends of messenger RNA to help stabilize it. The study suggests that both processes are regulated by a common mechanism.