Functional analysis of the integrator subunit 12 identifies a microdomain that mediates activation of the Drosophila integrator complex

Chen, Jiandong, Waltenspiel, Bernhard, Warren, William D., and Wagner, Eric. J. (2013) Functional analysis of the integrator subunit 12 identifies a microdomain that mediates activation of the Drosophila integrator complex. Journal of Biological Chemistry, 288 (7). pp. 4867-4877.

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The Drosophila integrator complex consists of 14 subunits that associate with the C terminus of Rpb1 and catalyze the endonucleolytic cleavage of nascent snRNAs near their 3' ends. Although disruption of almost any integrator subunit causes snRNA misprocessing, very little is known about the role of the individual subunits or the network of structural and functional interactions that exist within the complex. Here we developed an RNAi rescue assay in Drosophila S2 cells to identify functional domains within integrator subunit 12 (IntS12) required for snRNA 3' end formation. Surprisingly, the defining feature of the Ints12 protein, a highly conserved and centrally located plant homeodomain finger domain, is not required for reporter snRNA 3' end cleavage. Rather, we find a small, 45-amino acid N-terminal microdomain to be both necessary and nearly sufficient for snRNA biogenesis in cells depleted of endogenous IntS12 protein. This IntS12 microdomain can function autonomously, restoring full integrator processing activity when introduced into a heterologous protein. Moreover, mutations within the microdomain not only disrupt IntS12 function but also abolish binding to other integrator subunits. Finally, the IntS12 microdomain is sufficient to interact and stabilize the putative scaffold integrator subunit, IntS1. Collectively, these results identify an unexpected interaction between the largest and smallest integrator subunits that is essential for the 3' end formation of Drosophila snRNA.

Item ID: 25541
Item Type: Article (Research - C1)
ISSN: 1083-351X
Keywords: Drosophila, protein-protein interactions, RNA, RNA processing, transcription, termination, IntS12 microdomain, integrator complex, snRNA biosynthesis
Date Deposited: 04 Apr 2013 05:31
FoR Codes: 06 BIOLOGICAL SCIENCES > 0601 Biochemistry and Cell Biology > 060109 Proteomics and Intermolecular Interactions (excl Medical Proteomics) @ 50%
06 BIOLOGICAL SCIENCES > 0604 Genetics > 060405 Gene Expression (incl Microarray and other genome-wide approaches) @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
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