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Discovery of a pre-mRNA structural scaffold as a contributor to the mammalian splicing code [in vitro]

ABSTRACT: The specific recognition of splice signals at or near exon-intron junctions is not explained by their weak conservation and instead is postulated to require a multitude of features embedded in the pre-mRNA strand. We explored the possibility of three-dimensional structural scaffold of AdML – a model pre-mRNA substrate – guiding early spliceosomal components to the splice signal sequences. We find that mutations in the non-cognate splice signal sequences impede recruitment of early spliceosomal components due to disruption of the global structure of the pre-mRNA. We further find that the pre-mRNA segments potentially interacting with the early spliceosomal component U1 snRNP are distributed across the intron, that there is a spatial proximity of 5′ and 3′ splice sites within the pre-mRNA scaffold, and that an interplay exists between the structural scaffold and splicing regulatory elements in recruiting early spliceosomal components. These results suggest that early spliceosomal components can recognize a three-dimensional structural scaffold beyond the short splice signal sequences, and that in our model pre-mRNA, this scaffold is formed across the intron involving the major splice signals. This provides a conceptual basis to analyze the contribution of recognizable three-dimensional structural scaffolds to the splicing code across the mammalian transcriptome.

ORGANISM(S): Human adenovirus 2

PROVIDER: GSE173175 | GEO | 2021/06/23

REPOSITORIES: GEO

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Discovery of pre-mRNA structural scaffold as a contributor to mammalian splicing code [In Vivo]

Project description:The specific recognition of splice signals at or near the exon-intron junctions is not explained by their weak conservation across the mammalian transcriptome and postulated to require a multitude of features embedded in the pre-mRNA strand. We explored the possibility of three-dimensional structural scaffold of a pre-mRNA guiding early spliceosomal components to the splice signal sequences. We find that mutation in non-cognate splice signal sequences of a model pre-mRNA substrate could impede recruitment of early spliceosomal components due to disruption of global structure of the pre-mRNA. We also find distribution of pre-mRNA segments potentially interacting with early spliceosomal component U1 snRNP across the intron, spatial proximity of 5′ and 3′ splice sites within the pre-mRNA scaffold, and an interplay between the structural scaffold and splicing regulatory elements in recruiting early spliceosomal components. These results suggest that early spliceosomal components could recognize a three-dimensional structural scaffold beyond the short splice signal sequences and that in our model pre-mRNA, this scaffold is formed across the intron involving the major splice signals. This work provides a conceptual base to extend our understanding of prevalence, distribution, and splicing regulatory potential of recognizable three-dimensional structural scaffolds across the mammalian transcriptome.

2021-06-23 | GSE173177 | GEO

Cooperative engagement and subsequent selective displacement of SR proteins define the pre-mRNA 3D structural scaffold for early spliceosome assembly

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