The long term goal of this research is to reveal how gene expression is regulated at the post- transcriptional level. Control of messenger RNA (mRNA) translation and degradation underlies important biological processes including development, fertility and neurological functions. The proposed work focuses on the archetypal mRNA regulator, Pumilio (Pum). Pum is a member of the PUF family of eukaryotic RNA binding proteins. Pum binds an extensive group of messenger RNAs including those that encode key developmental morphogens. Upon binding to an mRNA, Pum represses expression of the encoded protein. The proposed research seeks to discover the mechanism of Pum repression and determine how Pum activity is modulated. We developed novel assays to measure Pum activity in Drosophila cells and discovered multiple new domains that potently repress protein expression. The repressive activity of the Pum repression domains do not rely on previously identified cofactors, indicating novel repression mechanism(s). In the first aim, we measure the impact of the repression domains on translation and mRNA degradation. We seek to discover cofactors necessary for their activity. We then investigate the role of each repression domain in the control of embryonic development. We discovered an autoregulatory switch that controls Pum activity and may be modulated by phosphorylation. In the second aim, we dissect the mechanism of this autoregulatory switch using functional and protein interaction assays. The role of Pum autoregulation during embryogenesis will be explored. This research will determine novel mechanisms of Pum repression and illuminate how that activity is regulated in response to protein modifications. The resulting discoveries are expected to broadly enhance our understanding of post-transcriptional control and specifically improve knowledge of gene regulation in development, fertility, stem cell proliferation, and the nervous system.

Public Health Relevance

This research is relevant to human biology and health because Pumilio proteins are conserved in humans where, like their Drosophila counterpart, they are implicated in control of cell proliferation, fertility and neurological functions. The RNA binding, repression and autoregulatory domains of Pumilio are homologous to human Pums; therefore, our discoveries are expected to be translatable to post-transcriptional regulation of human cancer biology, developmental defects, neurological disorders and infertility.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
7R01GM105707-04
Application #
9225476
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Bender, Michael T
Project Start
2013-09-20
Project End
2018-07-31
Budget Start
2016-01-01
Budget End
2016-07-31
Support Year
4
Fiscal Year
2015
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Biochemistry
Type
Schools of Medicine
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Goldstrohm, Aaron C; Hall, Traci M Tanaka; McKenney, Katherine M (2018) Post-transcriptional Regulatory Functions of Mammalian Pumilio Proteins. Trends Genet 34:972-990
T Abshire, Elizabeth; Chasseur, Jennifer; Bohn, Jennifer A et al. (2018) The structure of human Nocturnin reveals a conserved ribonuclease domain that represses target transcript translation and abundance in cells. Nucleic Acids Res 46:6257-6270
Wolfe, Michael B; Goldstrohm, Aaron C; Freddolino, Peter L (2018) Global analysis of RNA metabolism using bio-orthogonal labeling coupled with next-generation RNA sequencing. Methods :
Bohn, Jennifer A; Van Etten, Jamie L; Schagat, Trista L et al. (2018) Identification of diverse target RNAs that are functionally regulated by human Pumilio proteins. Nucleic Acids Res 46:362-386
Hughes, Kelsey L; Abshire, Elizabeth T; Goldstrohm, Aaron C (2018) Regulatory roles of vertebrate Nocturnin: insights and remaining mysteries. RNA Biol 15:1255-1267
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Lou, Tzu-Fang; Weidmann, Chase A; Killingsworth, Jordan et al. (2017) Integrated analysis of RNA-binding protein complexes using in vitro selection and high-throughput sequencing and sequence specificity landscapes (SEQRS). Methods 118-119:171-181
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