The long-term objectives of this proposed research are to understand the functions of members of the UNC-7/EAT-5 family of proteins in C. elegans. These proteins appear to be required for proper cell-cell coupling through gap junctions and eventually their role in specificity of neuronal connections, neuronal function, and embryonic development will be determined. unc-7 and related genes are postulated to encode invertebrate proteins that are functionally analogous to vertebrate connexins, gap junction channel proteins. This hypothesis will be tested by determining the subcellular structures with which these proteins associate and by examining the effect that family members have on gap junctional connections between cells. The location of the EMP protein, an embryonically expressed family member, will be examined by immunoelectron microscopy. Whether expression of unc-7 or emp can alter the properties of gap junction channels between insect cells in culture will be analyzed. Alternatively, whether UNC-7 or EMP protein can mediate dye-coupling in vertebrate tissue culture cells or in C. elegans oocytes will be tested. Additionally, whether there is loss of dye-coupling in cells of emp mutant embryos will be examined. The unc-7 gene is required in C. elegans for coordinated locomotion and is an additional focus of the investigations proposed here. unc-7 appears to affect several properties of neurons including the specificity of gap junctional connections between particular interneurons and motor neurons. The function of unc-7 will be investigated by analyzing which cells express unc-7, the location within these cells of the UNC-7 protein and the genetic lesions present in unc-7 mutants. Whether ectopic gap junctions observed in the nervous system of unc-7 mutants are responsible for the unc-7 uncoordinated phenotype will be tested by laser killing experiments. Genes whose products may interact with UNC- 7 or modulate UNC-7 function will be identified by isolating and beginning to characterize extragenic suppressors of unc-7 mutations. The expression of genes of the unc-7/eat-5 family will also be analyzed to have, eventually, a complete knowledge of the temporal and spatial expression pattern of all family members. The analysis will include, at this time, only family members expressed during early embryogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM056367-02
Application #
2771100
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1997-09-01
Project End
2001-08-31
Budget Start
1998-09-01
Budget End
1999-08-31
Support Year
2
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Genetics
Type
Schools of Arts and Sciences
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
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Von Stetina, Stephen E; Fox, Rebecca M; Watkins, Kathie L et al. (2007) UNC-4 represses CEH-12/HB9 to specify synaptic inputs to VA motor neurons in C. elegans. Genes Dev 21:332-46
Spartz, Angela K; Herman, Robert K; Shaw, Jocelyn E (2004) SMU-2 and SMU-1, Caenorhabditis elegans homologs of mammalian spliceosome-associated proteins RED and fSAP57, work together to affect splice site choice. Mol Cell Biol 24:6811-23
Starich, Todd A; Miller, Agnes; Nguyen, Rachel L et al. (2003) The Caenorhabditis elegans innexin INX-3 is localized to gap junctions and is essential for embryonic development. Dev Biol 256:403-17
Spike, Caroline A; Davies, Andrew G; Shaw, Jocelyn E et al. (2002) MEC-8 regulates alternative splicing of unc-52 transcripts in C. elegans hypodermal cells. Development 129:4999-5008
Phelan, P; Starich, T A (2001) Innexins get into the gap. Bioessays 23:388-96
Spike, C A; Shaw, J E; Herman, R K (2001) Analysis of smu-1, a gene that regulates the alternative splicing of unc-52 pre-mRNA in Caenorhabditis elegans. Mol Cell Biol 21:4985-95
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Davies, A G; Spike, C A; Shaw, J E et al. (1999) Functional overlap between the mec-8 gene and five sym genes in Caenorhabditis elegans. Genetics 153:117-34