Genomic structure and 5' regulatory regions of the let-23 gene in the nematode C. elegans

Journal of Molecular Biology
T SakaiY Ohshima

Abstract

The let-23 gene in the nematode Caenorhabditis elegans encodes a receptor tyrosine kinase and is necessary for the induction of a vulva, survival past the L1 stage, hermaphrodite fertility and for male spicule development. We sequenced the entire let-23 genomic region of over 12 kb. The 5' end of the let-23 mRNA was mapped by sequencing polymerase chain reaction products, and two mRNAs were found which had alternative exons and were probably initiated at different sites. One transcript was trans-spliced to SL1. Expression of either cDNA rescued a let-23 vulvaless mutation in germline transformation. These results suggest that the let-23 gene encodes two proteins of 1323 or 1335 amino acid residues. We prepared various 5' deletion constructs of the let-23 gene, and examined their rescue activities for a let-23 lethal or vulvaless mutation. The results revealed that two regions were required for let-23 expression, one for larval survival and the other for vulva formation. We also cloned and analyzed a let-23 homologue from Caenorhabditis vulgaris. It can encode two proteins of 77% amino acid residue identity with the Let-23 proteins. The 12 kb fragment carrying the C. vulgaris gene rescued the let-23 vulvaless mutation in C. eleg...Continue Reading

Citations

May 1, 1997·Molecular Biology of the Cell·G M Lesa, P W Sternberg

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