PgmNr D173: A high-throughput pipeline for the production of synthetic antibodies for analysis of ribonucleoprotein complexes.

Authors:
J. D. Laver 1 ; H. Na 1 ; J. Jeon 1 ; F. Singh 1 ; K. Ancevicius 1,2 ; Y. Fan 1 ; W. X. Cao 1 ; K. Nie 1 ; Z. Yang 1 ; H. Luo 1 ; M. Wang 1,3 ; O. Rissland 1,3 ; J. T. Westwood 2 ; P. M. Kim 1 ; S. S. Sidhu 1 ; C. A. Smibert 1 ; H. D. Lipshitz 1


Institutes
1) University of Toronto, Toronto, Ontario, CA; 2) University of Toronto at Mississauga, Mississauga, Ontario, Canada; 3) Hospital for Sick Children, Toronto, Ontario, Canada.


Keyword: RNA binding proteins

Abstract:

Post-transcriptional regulation of mRNAs plays an essential role in the control of gene expression. mRNAs are regulated in ribonucleoprotein (RNP) complexes by RNA-binding proteins (RBPs) along with associated protein and noncoding RNA (ncRNA) cofactors. A global understanding of post-transcriptional control in any cell type requires identification of the components of all of its RNP complexes. We have previously shown that these complexes can be purified by immunoprecipitation using anti-RBP synthetic antibodies produced by phage display. To develop the large number of synthetic antibodies required for a global analysis of RNP complex composition, we have established a pipeline that combines (i) a computationally aided strategy for design of antigens located outside of annotated domains, (ii) high-throughput antigen expression and purification in Escherichia coli, and (iii) high-throughput antibody selection and screening. Using this pipeline, we have produced 279 antibodies against 61 different protein components of Drosophila melanogaster RNPs. Together with those produced in our low-throughput efforts, we have a panel of 311 antibodies for 67 RNP complex proteins. Tests of a subset of our antibodies demonstrated that 89% immunoprecipitate their endogenous target from embryo lysate. We have successfully used synthetic antibodies in RNA co-immunoprecipitation experiments to identify the entire complement of mRNAs associated with each of three different RBPs – Staufen, Pumilio, and Brain Tumor – analysis of which provided significant insights into the functions of each of these proteins. This panel of antibodies will therefore serve as a valuable resource for global studies of RNP complexes in Drosophila. Furthermore, our high-throughput pipeline permits efficient production of synthetic antibodies against any large set of proteins.