Structural basis for RNA recognition by the C-terminal RRM domain of human RBM45

Area of Science:

• Molecular Biology
• Neuroscience
• Structural Biology

Background:

• RNA-binding motif 45 (RBM45) is crucial for neural development and RNA splicing.
• RBM45 dysfunction and aggregation are linked to neurodegenerative diseases like ALS and FTLD.
• RBM45 contains three RNA recognition motif (RRM) domains, but RRM3's RNA-binding properties are unknown.

Purpose of the Study:

• To investigate the RNA-binding specificity of the RBM45 RRM3 domain.
• To elucidate the molecular mechanism of RNA recognition by RBM45 RRM3.
• To understand the role of RBM45 RRM3 in the context of full-length RBM45 function.

Main Methods:

• RNA-binding assays to determine RRM3 specificity.
• X-ray crystallography to determine the structure of RBM45 RRM3 bound to DNA.
• Site-directed mutagenesis to analyze key amino acid residues in RNA binding.

Main Results:

• RBM45 RRM3 specifically binds RNA sequences containing GACG.
• The crystal structure reveals the molecular basis for GACG sequence recognition by RBM45 RRM3.
• Mutational analysis confirms the roles of specific residues in RBM45 RRM3 RNA binding.

Conclusions:

• The RBM45 RRM3 domain has distinct RNA sequence specificity compared to RRM1 and RRM2.
• The study provides a molecular mechanism for RBM45 RRM3-mediated RNA recognition.
• Findings lay the groundwork for understanding full-length RBM45 function in neurobiology.