Bicaudal-C associates with a Trailer Hitch/Me31B complex and is required for efficient Gurken secretion

TY - JOUR

T1 - Bicaudal-C associates with a Trailer Hitch/Me31B complex and is required for efficient Gurken secretion

AU - Kugler, Jan-Michael

AU - Chicoine, Jarred

AU - Lasko, Paul

PY - 2009/4/1

Y1 - 2009/4/1

N2 - Bicaudal-C (Bic-C) is a multiple KH-domain RNA-binding protein required for Drosophila oogenesis and, maternally, for embryonic patterning. In early oogenesis, Bic-C negatively regulates target mRNAs, including Bic-C, by recruiting the CCR4 deadenylase through a direct association with its NOT3 subunit. Here, we identify a novel function for Bic-C in secretion of the TGF-alpha homolog Gurken (Grk). In Bic-C mutant egg chambers, Grk is sequestered within actin-coated structures during mid-oogenesis. As a consequence, Egfr signalling is not efficiently activated in the dorsal-anterior follicle cells. This phenotype is strikingly similar to that of trailer hitch (tral) mutants. Consistent with the idea that Bic-C and Tral act together in Grk secretion, Bic-C co-localizes with Tral within cytoplasmic granules, and can be co-purified with multiple protein components of a Tral mRNP complex. Taken together, our results implicate translational regulation by Bic-C and Tral in the secretory pathway.

AB - Bicaudal-C (Bic-C) is a multiple KH-domain RNA-binding protein required for Drosophila oogenesis and, maternally, for embryonic patterning. In early oogenesis, Bic-C negatively regulates target mRNAs, including Bic-C, by recruiting the CCR4 deadenylase through a direct association with its NOT3 subunit. Here, we identify a novel function for Bic-C in secretion of the TGF-alpha homolog Gurken (Grk). In Bic-C mutant egg chambers, Grk is sequestered within actin-coated structures during mid-oogenesis. As a consequence, Egfr signalling is not efficiently activated in the dorsal-anterior follicle cells. This phenotype is strikingly similar to that of trailer hitch (tral) mutants. Consistent with the idea that Bic-C and Tral act together in Grk secretion, Bic-C co-localizes with Tral within cytoplasmic granules, and can be co-purified with multiple protein components of a Tral mRNP complex. Taken together, our results implicate translational regulation by Bic-C and Tral in the secretory pathway.

KW - Animals

KW - DEAD-box RNA Helicases

KW - Drosophila

KW - Drosophila Proteins

KW - Embryo, Nonmammalian

KW - Mutation

KW - Oogenesis

KW - RNA-Binding Proteins

KW - Ribonucleoproteins

KW - Transforming Growth Factor alpha

U2 - 10.1016/j.ydbio.2009.01.024

DO - 10.1016/j.ydbio.2009.01.024

M3 - Journal article

C2 - 19389362

SN - 0012-1606

VL - 328

SP - 160

EP - 172

JO - Developmental Biology

JF - Developmental Biology

IS - 1

ER -