LABORATORY MOUSE OF STRAIN C57BL/6JJACKSON LABORATORIESSearching for new mutations associated with neurodegenerative and cognitive defects, researchers have uncovered two mouse genes that function in the same critical pathway such that, when both are lost, neurodegeneration results. The genes are both involved in protein translation and, surprisingly, one encodes a transfer RNA (tRNA) gene uniquely expressed in the brain—a first example of such differential expression in vertebrates.
While, in theory, eukaryotes need to encode approximately 42 different tRNA genes—to decode the 61 messenger RNA (mRNA) triplet codons that specify an amino acid—the genomes of vertebrates contain hundreds of tRNA genes. So far, researchers have presumed that the redundancy exists because a large amount of these tRNAs are needed to meet the demands of constant translation of mRNAs to proteins. Also surprising was the pre-existence of this tRNA mutation only in a specific, widely studied strain of laboratory mice. The work, published today (July 24) in Science, suggests that, rather than being redundant, some of these tRNA genes may have tissue-specific functions.
“It has been assumed that more tRNA genes just make more tRNAs, but this study very strongly suggests that specific tRNA ...
