2002 East Coast Worm Meeting abstract 95
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| 1 | Department of Molecular Biology, Princeton University, Princeton, NJ 08544 |
| 2 | Department of Biology, Campus Box 7388, Baylor University, Waco, TX 76798 |
Heterodimeric integrin receptors play vital roles in bi-directional signaling during tissue development, organization, remodeling, and repair. The b integrinsubunit cytoplasmic domain is essential for transmission of many of these signals. Unlike vertebrates, which have multiple b subunit genes, the nematode Caenorhabditis elegans expresses only one b subunit (bpat-3) and a null mutation in this gene causes embryonic lethality. To determine the functions of bpat-3 during larval development and in adult tissues, we have established several C. elegans rescued lines expressing bPAT-3 integrin with specific cytoplasmic tail mutations. A wild type bpat-3 allele (pat-3(+)) and alleles with Tyr to Phe mutations (pat-3 (Y792F), pat-3(Y804F) and pat-3(YYFF)) in the cytoplasmic domain were able to rescue pat-3 null animals. Animals rescued with mutant alleles of bpat-3integrin display cell migration defects. During normal C. elegans development, the two arms of the hermaphrodite gonad extend to form a U-shaped structure, but in the pat-3 (Y792F), pat-3(Y804F) and pat-3(YYFF) mutant rescued lines, gonad morphology is abnormal. In the mutant animals, gonadal distal tip cells do not follow the normal path along the dorsal body wall resulting in mislocalized and misshapen gonad arms. Integrins are known be involved in the assembly and stabilization of muscle cytoskeleton. Immunofluorescence staining of rescued lines with anti-PAT-3 antibodies showed that wild type and mutant b integrins were each distributed in a dotted pattern along the length of muscle cells, indicative of proper localization to dense bodies/focal adhesions. Rescued animals show normal movement and egg laying, indicating that muscle functions are not affected by tyrosine mutations of the bPAT-3 tail. Detailed phenotypic analysis of rescued animals will be used to more fully define the role of the bPAT-3 tail tyrosine residues in tissue-specific integrin functions.