High impact information on SNU114

• The EF-G-like GTPase Snu114p regulates spliceosome dynamics mediated by Brr2p, a DExD/H box ATPase [1].
• Moreover, a single amino acid substitution in the G1 sequence motif of Snu114p, expected to abolish GTP-binding activity, is lethal, suggesting that GTP binding and probably GTP hydrolysis is important for the function of U5-116kD/Snu114p [2].
• The G domain of U5-116kD/Snu114p contains the consensus sequence elements G1-G5 important for binding and hydrolyzing GTP [2].
• A 114 kDa protein (Snu114p) homologous to U5-116kD was identified in Saccharomyces cerevisiae and was shown to be essential for yeast cell viability [2].
• Mutagenesis suggests several roles of Snu114p in pre-mRNA splicing [3].

Biological context of SNU114

• We propose that GTP hydrolysis results in a rearrangement between Prp8 and the C terminus of Snu114 that leads to release of U1 and U4, thus activating the spliceosome for catalysis [4].
• To assess the functional importance of the domains of Snu114, we used random mutagenesis to create conditionally lethal alleles [4].
• An arginine residue in domain II, which in EF-G forms a salt bridge with a residue of the G domain, when mutated in Snu114p (R487E), led to a temperature-sensitive phenotype [3].

Anatomical context of SNU114

• Genetic analysis reveals a role for the C terminus of the Saccharomyces cerevisiae GTPase Snu114 during spliceosome activation [4].
• To test whether Snu114p in the spliceosome is involved in rearranging RNA secondary structures (by analogy to EF-2 in the ribosome), we created conditionally lethal mutants [5].

References