Genetics, May 2018, Vol.209(1), pp.173-193
Covalent attachment of ubiquitin to substrate proteins changes their function or marks them for proteolysis, and the specificity of ubiquitin attachment is mediated by the numerous E3 ligases encoded by animals. Mind Bomb is an essential E3 ligase during Notch pathway signaling in insects and vertebrates. While encodes a Mind Bomb homolog (), it has never been recovered in the extensive Notch suppressor/enhancer screens that have identified numerous pathway components. Here, we show that null mutants have a spermatogenesis-defective phenotype that results in a heterogeneous mixture of arrested spermatocytes, defective spermatids, and motility-impaired spermatozoa. mutants also have chromosome segregation defects during meiosis, molecular null mutants are intrinsically temperature-sensitive, and many spermatids contain large amounts of tubulin. These phenotypic features are similar to the endogenous RNA intereference (RNAi) mutants, but mutants do not affect RNAi. MIB-1 protein is expressed throughout the germ line with peak expression in spermatocytes followed by segregation into the residual body during spermatid formation. expression, while upregulated during spermatogenesis, also occurs somatically, including in vulva precursor cells. Here, we show that mutants suppress both and ( Notch) gain-of-function mutants, restoring anchor cell formation and a functional vulva to the former and partly restoring oocyte production to the latter. However, suppressed hermaphrodites are only observed when grown at 25°, and they are self-sterile. This probably explains why was not previously recovered as a Notch pathway component in suppressor/enhancer selection experiments.
C. Elegans ; Mind Bomb ; Notch Signaling ; Spermatogenesis ; Ubiquitin E3 Ligase ; Caenorhabditis Elegans -- Genetics ; Caenorhabditis Elegans Proteins -- Metabolism ; Glucagon-Like Peptide 1 -- Metabolism ; Ki-67 Antigen -- Genetics ; Receptors, Notch -- Metabolism ; Spermatogenesis -- Genetics
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