RESUMEN
RNAi is a widespread mechanism by which organisms regulate gene expression and defend their genomes against viruses and transposable elements. Here we report the identification of Drosophila zucchini (zuc) and squash (squ), which function in germline RNAi processes. Zuc and Squ contain domains with homologies to nucleases. Mutant females are sterile and show dorsoventral patterning defects during oogenesis. In addition, Oskar protein is ectopically expressed in early oocytes, where it is normally silenced by RNAi mechanisms. Zuc and Squ localize to the perinuclear nuage and interact with Aubergine, a PIWI class protein. Mutations in zuc and squ induce the upregulation of Het-A and Tart, two telomere-specific transposable elements, and the expression of Stellate protein in the Drosophila germline. We show that these defects are due to the inability of zuc and squ mutants to produce repeat-associated small interfering RNAs.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimología , Embrión no Mamífero/metabolismo , Endonucleasas/metabolismo , Endorribonucleasas/metabolismo , Células Germinativas/metabolismo , Oogénesis/fisiología , ARN Interferente Pequeño/farmacología , Secuencia de Aminoácidos , Animales , Northern Blotting , Western Blotting , Elementos Transponibles de ADN/fisiología , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Endonucleasas/genética , Endorribonucleasas/genética , Femenino , Regulación Fúngica de la Expresión Génica , Productos del Gen gag/metabolismo , Células Germinativas/citología , Inmunoprecipitación , Masculino , Datos de Secuencia Molecular , Mutación , Oocitos/citología , Oocitos/metabolismo , Factores de Iniciación de Péptidos/metabolismo , ARN de Hongos/genética , ARN de Hongos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Homología de Secuencia de Aminoácido , Factor de Crecimiento Transformador alfa/metabolismoRESUMEN
The deadlock gene is required for a number of key developmental events in Drosophila oogenesis. Females homozygous for mutations in the deadlock gene lay few eggs and those exhibit severe patterning defects along both the anterior-posterior and dorsal-ventral axis. In this study, we analyzed eggs and ovaries from deadlock mutants and determined that deadlock is required for germline maintenance, stability of mitotic spindles, localization of patterning determinants, oocyte growth and fusome biogenesis in males and females. Deadlock encodes a novel protein which colocalizes with the oocyte nucleus at midstages of oogenesis and with the centrosomes of early embryos. Our genetic and immunohistological experiments point to a role for Deadlock in microtubule function during oogenesis.