Effects of spliceosomal mutations on brain patterning and morphogenesis

Abstract

The major spliceosome consists of U1, U2, U5, and U4/U6 small nuclear ribonucleoprotein (snRNPs), and each snRNP has distinct and sequential roles during the mRNA splicing process. Mutations in the core components of the spliceosome are associated with brain and neurological defects. The goal of this study is to examine the role of three core spliceosomal components, SNRPB, SF3B4, and EFTUD2, in brain patterning and morphogenesis, and whether or not they are required in the neural tube or neural crest cells for brain development. Previously, we identified brain defects associated with the mutation of these spliceosomal components in the neural tube and neural crest cells. Structures derived from the midbrain and hindbrain region, such as the diencephalon, pons, and cerebellum, were found to be absent in E12.5 and E14.5 mutant embryos. In this study, we aim to use mutant mouse models to identify shared transcripts and pathways disrupted by mutations in these spliceosomal genes. Through RNA‐seq analysis, we identified a number of mis‐expressed RNA‐binding proteins that may contribute to the malformationis found in these mutants. We plan to examine level and expression of these RNA binding proteins in wild type and mutant embryos to evaluate how they contribute to the phenotypes found. Furthermore, to assess the potential clinical application of our findings, we will use human embryonic stem cells (hESC) to generate human neural crest cells with mutatioin in these splicing factors; shared transcripts and pathways identified in the mouse model will be compared to those found in induced human neural crest cells. Distinct spliceosomophathies are difficult to diagnose due to phenotypic overlaps. The significance of this work lies in its potential to identify a disrupted pathway shared by mutations in various splicing factors, a therapeutic alternative across multiple spliceosomopathies.