Functional, developmentally expressed genes for mouse U1a and U1b snRNAs contain both conserved and non-conserved transcription signals

摘要

Four genes that encode mouse Ula1, Ulb2 and Ulb6 snRNAs have been isolated from a mouse genomic DNA library. They all appear to be functional U1 genes since they are accurately transcribed into full length, capped snRNAs upon injection into Xenopus oocytes. A mouse pseudogene that is not transcribed in Xenopus oocytes was also isolated from the mouse genomic library. DNA sequence analysis of the 5' and 3' flanking regions of the functional genes revealed the presence of three highly conserved sequence elements that have been shown to be required for transcription initiation or 3' end formation in other Ul genes. Each of these Ul RNA genes also contains non-conserved sequences in the 5' flanking region that could function in their controlled expression during development.