| Popis: |
Many spliceosomal DExD/H box helicases act as fidelity factors during pre-mRNA splicing, promoting on-pathway interactions while simultaneously minimizing errors. Mutations linked to Retinitis Pigmentosa (RP), a form of heritable blindness, map to key domains of spliceosomal helicase Brr2 (SNRNP200in humans). Previous data show that such mutations negatively impact spliceosome activation, likely due to defects inbrr2-RPRNA binding, helicase, and ATPase activities. Furthermore, data from human reporter constructs suggest thatbrr2-RPmight impact 5′ splice site selection. Here we undertake a systematic analysis ofbrr2-RPeffects on splicing fidelity. We show that a subset ofbrr2-RPmutants exhibit intron retentionin vivo. Furthermore,brr2-RPmutants display hyperaccurate and/or error-prone splicing of a variety of splicing reporters. Branch-site fidelity is particularly impacted in this reporter assay. In addition, multiplebrr2-RPalleles genetically interact withprp16alleles known to impact the fidelity of branch site selection. Together these data implicate Brr2 in the fidelity of branch-site selection, and suggest that RP results not just from defects in spliceosome activation, but also from fidelity defects arising throughout the splicing cycle and in splicing fidelity. |
