Work

A Sequential Binding Mechanism for 5’ Splice Site Recognition and Modulation for the Human U1 snRNP

Year: 2024

Type: preprint

Abstract: Splice site recognition is essential for defining the transcriptome. Drugs like risdiplam and branaplam change how U1 snRNP recognizes particular 5' splice sites (5'SS) and promote U1 snRNP binding and splicing at these locations. Despite the therapeutic potential of 5'SS modulators, the complexity of their interactions and snRNP substrates have precluded defining a mechanism for 5'SS modulation. We have determined a sequential binding mechanism for modulation of -1A bulged 5'SS by branaplam using a combination of ensemble kinetic measurements and colocalization single molecule spectroscopy (CoSMoS). Our mechanism establishes that U1-C protein binds reversibly to U1 snRNP, and branaplam binds to the U1 snRNP/U1-C complex only after it has engaged a -1A bulged 5'SS. Obligate orders of binding and unbinding explain how reversible branaplam interactions cause formation of long-lived U1 snRNP/5'SS complexes. Branaplam is a ribonucleoprotein, not RNA duplex alone, targeting drug whose action depends on fundamental properties of 5'SS recognition.

Source: bioRxiv (Cold Spring Harbor Laboratory)

DOI: 10.1101/2024.04.18.590139

Authors: David S. White, Bryan M. Dunyak, Frédéric H. Vaillancourt, Aaron A. Hoskins

Institutions: University of Wisconsin–Madison, Elements Biosciences (United States)

Language: English

Topic: RNA Research and Splicing

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funder: National Institutes of Health

Awards: G9000065035, G9000070464, G9000218216