Poster abstracts
Poster number 113 submitted by Peyton Russelburg
Time Flies: Evolutionary Changes in Drosophila SNF RNA Binding Proteins
L. Peyton Russelburg (Biology Department, University of Southern Indiana), Kim Delaney (Biology Department, University of Southern Indiana)
Abstract:
The complex machinery of the spliceosome consists of both RNA and proteins to facilitate a key step in mRNA processing: RNA splicing. The U1A/U2Bʹʹ/SNF protein family participates in both the U1 and U2 snRNPs of the spliceosome. This protein family is well studied because of its unique, high affinity RNA binding interactions. Most metazoans have a single protein, SNF, which binds RNA stemloops in both the U1 and U2 snRNPs; however a gene duplication event in a predecessor of jawed vertebrates gave rise to paralogous family members which rapidly specialized. This resulted in U1A, which segregates to the U1 snRNP, and U2Bʹʹ, which segregates to the U2 snRNP.
Reconstruction of ancestral SNF proteins has given insight into the mechanisms of modern U1A affinity and specificity. Previous work has informed the evolutionary development of the vertebrate proteins; we now turn our interest to the evolutionary pathway of Drosophila SNF. Two early SNF proteins have been selected for initial investigation. One is the last common ancestor of the genus Drosophila (LCA-D) and the other the last common ancestor of fruit flies (LCA-F). After phylogenetic analysis of U1A/U2Bʹʹ/SNF protostome lineages, we used ancestral reconstruction to resurrect the sequences of LCA-D and LCA-F. We aim to characterize the behavior and binding mechanisms of these two ancestral SNF proteins. Understanding of the evolutionary development of SNF’s affinity and specificity for its two unique RNA targets will lead to further insight into the divergence and specialization of U1A and U2Bʹʹ.
Keywords: RRM, U1ASNF, Ancestral Reconstruction