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K L Hudson

Publications and source records attributed to K L Hudson.

4 recordsLinked to original sources
PubMed1991

Dominant and recessive mutations define functional domains of Toll, a transmembrane protein required for dorsal-ventral polarity in the Drosophila embryo.

The asymmetry of the dorsal-ventral pattern of the Drosophila embryo appears to depend on the ventral activation of the transmembrane Toll protein. The Toll protein is found around the entire dorsal-ventral circumference of the embryo, and it appears to act as a receptor for a ventral, extracellular signal and to then relay that signal to the cytoplasm in ventral regions of the embryo. Three of five recessive loss-of-function alleles of Toll are caused by point mutations in the region of the cytoplasmic domain of Toll that is similar to the mammalian interleukin-1 receptor, supporting the hypothesis that Toll acts as a signal-transducing receptor. Nine dominant gain-of-function alleles that cause Toll to be active in dorsal, as well as ventral, regions of the embryo are caused by mutations in the extracellular domain. Three of the dominant alleles appear to cause the protein to be constitutively active and are caused by cysteine-to-tyrosine changes immediately outside the transmembrane domain. All six of the remaining dominant alleles require the presence of a wild-type transmembrane Toll protein for their ventralizing effect and all encode truncated proteins that lack the transmembrane and cytoplasmic domains.

Alleles↗
PubMed1988

The Toll gene of Drosophila, required for dorsal-ventral embryonic polarity, appears to encode a transmembrane protein.

The Toll gene of Drosophila, a maternal effect gene that plays a central role in the establishment of the embryonic dorsal-ventral pattern, has been cloned using P element tagging. A 5.3 kb poly(A)+ ovarian transcript from the cloned region was purified by hybrid selection with the cloned DNA. This purified transcript complements the Toll mutant phenotype when injected into Toll- embryos, which proves that it is the Toll transcript. The sequence of cDNAs suggests that the Toll protein is an integral membrane protein with a cytoplasmic domain and a large extracytoplasmic domain. The putative extracytoplasmic domain contains at least 15 repeats of a 24 amino acid, leucine-rich sequence found in both human and yeast membrane proteins.

Alleles↗