The function and fate of any given cell is determined by the gene expression profile of that cell. While transcription plays a key role in determining gene expression, post-transcriptional regulatory events also are of vital importance in determining the spatial and temporal pattern of gene expression. One crucial post- transcriptional step is addition of a polyadenosine or poly(A) tail following 3'-end cleavage of mRNA. This poly(A) tail modulates numerous events including mRNA export from the nucleus, translation, transport and turnover, largely via the recruitment of polyadenosine RNA binding proteins (Pabs). Polyadenylation of additional classes of RNA has also been implicated in quality control. The critical importance of proper polyadenylation and Pab protein function is evident in the number of human diseases that arise due to mutations in genes encoding these proteins. In the previous funding cycle, we collaborated to identify mutations in the human ZC3H14 gene, which encodes a ubiquitously expressed, evolutionarily conserved, zinc finger, nuclear polyadenosine RNA binding protein (Pab), that cause an autosomal recessive form of non- syndromic intellectual disability (previously termed mental retardation). These patients have severely impaired brain function with IQs in the range of 35-50 as compared to an average adult IQ range of 90-110. Although little is known about the function of ZC3H14, studies of the budding yeast (Nab2) and Drosophila counterparts (dNab2) provide compelling evidence that this class of proteins plays an evolutionarily conserved role in regulating poly(A) tail length. The broad, long-term objective of this proposal is to define how poly(A) tail length is regulated by the zinc finger Pabs to understand both the critical role in post-transcriptional regulation of gene expression and the mechanisms underlying neuronal defects in affected patients. This proposal exploits exciting preliminary data collected through studies of this evolutionarily conserved class of proteins in budding yeast, Drosophila, and cultured neuronal cells capitalizing on established tools and models. These studies strongly implicate the complex of 3'-5 riboexonucleases known as the nuclear exosome in cooperating with Nab2 to regulate poly(A) tail length. Based on preliminary data, we will test the hypothesis that the Nab2 class of RNA binding proteins cooperates with the exosome to regulate poly(A) tail length of RNA thus ensuring proper neuronal function. This hypothesis will be tested through three complementary Specific Aims that seek to: 1) define a molecular mechanism for Nab2/ZC3H14 in regulating poly(A) tail length (Aim 1);extend these studies into our established Drosophila model to link molecular mechanisms to neuronal function (Aim 2);and finally determine whether specific RNAs or classes of RNAs accumulate extended poly(A) tails upon loss of Nab2/ZC3H14 function (Aim 3). Successful completion of these aims will provide insight into a critical point in post-transcriptional regulation of gene expression mediated by a recently described family of Pab proteins and also lend insight into the molecular defects underlying intellectual disability in patients.

Public Health Relevance

This proposal seeks to understand the function of a protein that we recently found is altered in patients who have a disease called intellectual disability where their brain function is severely impaired (a disease previously termed mental retardation). The type of protein that is defective in these patients binds to the end or poly(A) tail of the messenger sequences or mRNAs that carry information from the genetic material in the cell nucleus to the cytoplasm where the information can be decoded. These proteins are very important for regulating how that information is read and thus understanding their function will provide important information both about how cells decode genes and about what is wrong in the brains of patients who suffer from this form of intellectual disability.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM058728-13A1
Application #
8531541
Study Section
Special Emphasis Panel (ZRG1-GGG-A (02))
Program Officer
Bender, Michael T
Project Start
1999-02-01
Project End
2017-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
13
Fiscal Year
2013
Total Cost
$356,868
Indirect Cost
$126,868
Name
Emory University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Morris, Kevin J; Corbett, Anita H (2018) The polyadenosine RNA-binding protein ZC3H14 interacts with the THO complex and coordinately regulates the processing of neuronal transcripts. Nucleic Acids Res 46:6561-6575
Morton, Derrick J; Kuiper, Emily G; Jones, Stephanie K et al. (2018) The RNA exosome and RNA exosome-linked disease. RNA 24:127-142
Corbett, Anita H (2018) Post-transcriptional regulation of gene expression and human disease. Curr Opin Cell Biol 52:96-104
Fasken, Milo B; Losh, Jillian S; Leung, Sara W et al. (2017) Insight into the RNA Exosome Complex Through Modeling Pontocerebellar Hypoplasia Type 1b Disease Mutations in Yeast. Genetics 205:221-237
Bienkowski, Rick S; Banerjee, Ayan; Rounds, J Christopher et al. (2017) The Conserved, Disease-Associated RNA Binding Protein dNab2 Interacts with the Fragile X Protein Ortholog in Drosophila Neurons. Cell Rep 20:1372-1384
Rha, Jennifer; Jones, Stephanie K; Fidler, Jonathan et al. (2017) The RNA-binding protein, ZC3H14, is required for proper poly(A) tail length control, expression of synaptic proteins, and brain function in mice. Hum Mol Genet 26:3663-3681
Limpose, Kristin L; Corbett, Anita H; Doetsch, Paul W (2017) BERing the burden of damage: Pathway crosstalk and posttranslational modification of base excision repair proteins regulate DNA damage management. DNA Repair (Amst) 56:51-64
Wigington, Callie P; Morris, Kevin J; Newman, Laura E et al. (2016) The Polyadenosine RNA-binding Protein, Zinc Finger Cys3His Protein 14 (ZC3H14), Regulates the Pre-mRNA Processing of a Key ATP Synthase Subunit mRNA. J Biol Chem 291:22442-22459
Fasken, Milo B; Corbett, Anita H (2016) Links between mRNA splicing, mRNA quality control, and intellectual disability. RNA Dis 3:
Kelly, Seth M; Bienkowski, Rick; Banerjee, Ayan et al. (2016) The Drosophila ortholog of the Zc3h14 RNA binding protein acts within neurons to pattern axon projection in the developing brain. Dev Neurobiol 76:93-106

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