CAR-1, a Protein That Localizes with the mRNA Decapping Component DCAP-1, Is Required for Cytokinesis and ER Organization inCaenorhabditis elegansEmbryos

Abstract

The division of one cell into two requires the coordination of multiple components. We describe a gene, car-1, whose product may provide a link between disparate cellular processes. Inhibition of car-1 expression in Caenorhabditis elegans embryos causes late cytokinesis failures: cleavage furrows ingress but subsequently regress and the spindle midzone fails to form, even though midzone components are present. The localized accumulation of membrane that normally develops at the apex of the cleavage furrow during the final phase of cytokinesis does not occur and organization of the endoplasmic reticulum is aberrant, indicative of a disruption in membrane trafficking. The car-1 gene has homologues in a number of species, including proteins that associate with RNA binding proteins. CAR-1 localizes to P-granules (germ-line specific ribonucleoprotein particles) and discrete, developmentally regulated cytoplasmic foci. These foci also contain DCAP-1, a protein involved in decapping mRNAs. Thus, CAR-1, a protein likely to be associated with RNA metabolism, plays an essential role in the late stage of cytokinesis, suggesting a novel link between RNA, membrane trafficking and cytokinesis in the C. elegans embryo.

CPEB Interacts with an Ovary-specific eIF4E and 4E-T in Early Xenopus Oocytes

“…41, 42, and 71). For example, Xp54 (Dhh1, Me31B, Cgh-1, and RCK) and RAP55 (Scd6, Tral, and CAR-1) proteins localize to P bodies in yeast and mammalian cells (37,40,74), in Drosophila S2 cells (71), and neuronal granules (45), in germinal granules in Drosophila oocytes (69,75), and in P granules in C. elegans embryos (44,68,76). In Drosophila, Orb, Me31B, Tral, and Cup localize within the future oocyte in developing regions 2 and 3 of the germarium, composed of germ line cysts, and are associated with the Balbiani body (69,75,77).…”

RAP55, a Cytoplasmic mRNP Component, Represses Translation in Xenopus Oocytes

“…Recently, diverse functions have been reported for C. elegans and Drosophila homologues of RAP55, CAR-1, and Trailer hitch (Tral), respectively (56). In C. elegans CAR-1 is required for embryonic cytokinesis, regulation of physiological germ line apoptosis, and organization of the endoplasmic reticulum (49,50,57). Depletion of CAR-1 leads to a defect in cytokinesis during early embryogenesis resulting from an anaphase spindle defect (57).…”

“…In C. elegans CAR-1 is required for embryonic cytokinesis, regulation of physiological germ line apoptosis, and organization of the endoplasmic reticulum (49,50,57). Depletion of CAR-1 leads to a defect in cytokinesis during early embryogenesis resulting from an anaphase spindle defect (57). In Drosophila oocytes and nurse cells, Tral is associated with a subset of endoplasmic reticulum exit sites and is required for the proper secretion of proteins such as Gurken and Yolkless (58).…”

Germ Cell Apoptosis and DNA Damage Responses

“…However, inactivation of these and other genes by mutation or RNAi leads to additional germline defects, such as an extended pachytene zone, reduced progeny, full or partial sterility, or a generally misshapen germline (Audhya et al 2005 ;Green et al 2011 ;Squirrell et al 2006 ) . Thus excessive apoptosis might be a secondary consequence of pleiotropic germ cell defects.…”