Mer1p is a modular splicing factor whose function depends on the conserved U2 snRNP protein Snu17p.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Mer1p is essential for meiotic splicing of specific pre-mRNAs in Saccharomyces cerevisiae.
• Previous research highlighted U1 snRNP involvement in Mer1p-activated splicing.
• The precise mechanisms and stages of Mer1p's regulatory function remain incompletely understood.

Purpose of the Study:

• To investigate the functional domains of Mer1p and their roles in splicing activation.
• To determine if Mer1p's enhancer recognition is separable from its splicing activation function.
• To elucidate the specific steps of spliceosome assembly influenced by Mer1p.

Main Methods:

• Analysis of Mer1p's C-terminal KH-type RNA-binding domain and N-terminal domain.
• Assays for Mer1p-activated splicing with mutated branch point sequences.
• Investigating Mer1p's function in the absence of Snu17p.
• Two-hybrid assays to identify Mer1p interacting proteins.

Main Results:

• Mer1p's RNA-binding domain recognizes splicing enhancers, while its N-terminal domain interacts with the spliceosome.
• Mer1p can activate splicing even with mutated branch point sequences.
• Mer1p requires Snu17p and interacts with Mud2p, Bbp1p, and Prp11p for splicing activation.

Conclusions:

• Mer1p functions as a modular splicing regulator.
• Mer1p activates splicing at multiple early stages of spliceosome assembly.
• Mer1p's activity depends on the coordinated function of U1 and U2 snRNP components.