Genetic dissection of the U4/U6/U5 snRNP “cycle’ in yeast

✍ Scribed by Christine Guthrie; Karen Shannon; Remy Bordonne

• Book ID: 104738784
• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 106 KB
• Volume: 14
• Category: Article
• ISSN: 0301-4851
• DOI: 10.1007/bf00360448

✦ Synopsis

We are applying a genetic approach toward understanding the mechanism and structural significance of the dynamic change in behavior of the U4/U6 and U5 snRNPs during splicing. We have postulated previously that U4 and U6 are tightly associated via an extensive hydrogen-bonding interaction (Brow and Guthrie, 1988); 23 base-pairs can be formed between a contiguous region in U6 and two complementary regions in U4 which are interrupted by a conserved intramolecular stem/loop. We have now provided genetic evidence for the existence of this interaction domain by the creation of mutations which destroy and restore base-pairing potential. As expected, mutations predicted to destabilize the intermolecular helix have a lowered Tm in an in vitro assay. Curiously, however, these mutants have a cold-sensitive phenotype in vivo. Since wild-type growth is restored only when base-pairing is possible, the lethality must be due to the alteration in the helix per se.