Notch Research Lags Ahead

Science's STKE  23 May 2000:
Vol. 2000, Issue 33, pp. tw6
DOI: 10.1126/stke.2000.33.tw6

Using a modification of the yeast two-hybrid assay to find transcription factors involved in Notch signaling, Petcherski and Kimble identified LAG-3, a protein that could only bind to the Notch pathway DNA binding protein LAG-1, in the presence of the intracellular domain of GLP-1 (Notch receptor). LAG-3 did not bind to LAG-1 alone. Immunoprecipitation experiments revealed that GLP-1 associated very weakly with LAG-3 and that this complex was much more stable in the presence of LAG-1. Inhibition of expression of GLP-1 or LAG-3 by RNA interference in Caenorhabditis elegans yielded animals that failed to develop pharynxes and died within their eggshells. Fluorescence assays indicated that epitope-tagged LAG-3 protein localized to the nucleus. Also, a LexA-LAG-3 fusion protein was observed to strongly activate transcription in yeast. Thus, it is likely that LAG-3 is a transcriptional activator, and the intracellular domain of Notch (GLP-1) acts to bring LAG-1 and LAG-3 together at specific promoter sites.

Petcherski, A.G., and Kimble, J. (2000) LAG-3 is a putative transcriptional activator in the C. elegans Notch pathway. Nature 405: 364-368. [Online Journal]