A ubiquitin-conjugating enzyme, ube2d3.2, regulates xMLK2 and pronephros formation in Xenopus.
The Jun N-terminal kinase kinase kinase MLK2 is required for the formation of the pronephros during early Xenopus development. Here, we have used a yeast 2-hybrid screen to identify proteins that interact with and regulate xMLK2. Using an N-terminal polypeptide encompassing the SH3 and kinase domains of xMLK2 as bait, five independent cDNAs were identified, all of which encoded a Xenopus ubiquitin conjugating enzyme, ube2d3.2. Ube2d3.2 is a functional E2 enzyme expressed maternally and in a tissue-restricted fashion during development. Ectopic expression of ube2d3.2 inhibits formation of the pronephric tubules, resulting in a phenotype very similar to the loss of xMLK2 function. Because ube2d3.2 is also shown to limit accumulation of xMLK2, it is likely that this effect is direct, although other explanations are possible. Ube2d3.2 is thus probably an endogenous regulator of xMLK2, and hence of JNK activity.
Jean
Steve
S
Department of Medical Biology, Cancer Research Centre, Laval University, CHUQ-HDQ, Pavillon St. Patrick, 9 rue McMahon, Québec, Canada G1R 3S3.
Moss
Tom
T
D000818:Animals; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D017403:In Situ Hybridization; D007668:Kidney / Q000196:embryology*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics*; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism / Q000502:physiology*; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins / Q000235:genetics*
D029867:Xenopus Proteins; D044763:Ubiquitin-Conjugating Enzymes; D020930:MAP Kinase Kinase Kinases; C490540:map3k10 protein, Xenopus