Split-APEX implicates splicing factor SRSF1 and splicing helicases in ribosomal biogenesis.

Area of Science:

• Molecular Biology
• Cellular Biology
• Biochemistry

Background:

• SR proteins are RNA-binding proteins essential for various cellular processes, including transcription and translation.
• SRSF1, a well-known SR protein, is involved in RNA splicing and spliceosome assembly, interacting with RNA helicases like DDX23.

Purpose of the Study:

• To investigate the role of SRSF1 in other steps of spliceosome assembly and reaction.
• To identify proteins in proximity to SRSF1 during spliceosome dynamics using split-APEX technology.

Main Methods:

• Utilized split-APEX proximity labeling with SRSF1 and various RNA helicases involved in different spliceosome steps.
• Analyzed biotinylated proteins to identify SRSF1 interactors and proximal proteins in spliceosome complexes.

Main Results:

• All tested helicases complemented SRSF1, indicating interactions or proximity.
• Identified proximal proteins primarily belonged to two categories: splicing-related proteins and ribosomal proteins.
• The proximity profiles were remarkably similar across different helicase interactions with SRSF1.

Conclusions:

• SRSF1 and canonical helicases may have previously unrecognized collaborative functions in ribosomal assembly.
• These findings suggest potential new roles for SR proteins and helicases in translation processes.
• The study expands the understanding of SR protein involvement beyond splicing into ribosome biogenesis and translation.