title: Innexin2 gap junctions in somatic support cells are required for cyst formation and for egg chamber formation in Drosophila.
abstract: Germ cells require intimate associations with surrounding somatic cells during gametogenesis. During oogenesis, gap junctions mediate communication between germ cells and somatic support cells. However, the molecular mechanisms by which gap junctions regulate the developmental processes during oogenesis are poorly understood. We have identified a female sterile allele of innexin2 (inx2), which encodes a gap junction protein in Drosophila. In females bearing this inx2 allele, cyst formation and egg chamber formation are impaired. In wild-type germaria, Inx2 is strongly expressed in escort cells and follicle cells, both of which make close contact with germline cells. We show that inx2 function in germarial somatic cells is required for the survival of early germ cells and promotes cyst formation, probably downstream of EGFR pathway, and that inx2 function in follicle cells promotes egg chamber formation through the regulation of DE-cadherin and Bazooka (Baz) at the boundary between germ cells and follicle cells. Furthermore, genetic experiments demonstrate that inx2 interacts with the zero population growth (zpg) gene, which encodes a germline-specific gap junction protein. These results indicate a multifunctional role for Inx2 gap junctions in somatic support cells in the regulation of early germ cell survival, cyst formation and egg chamber formation. Inx2 gap junctions may mediate the transfer of nutrients and signal molecules between germ cells and somatic support cells, as well as play a role in the regulation of cell adhesion.
authors: Department of Biology, Faculty of Science and Engineering, Konan University, Okamoto, Higashinada, Kobe, Japan. mmukai01@center.konan-u.ac.jp
authors: Masanori
authors: M
authors: Mukai
authors: Hirotaka
authors: H
authors: Kato
authors: Seiji
authors: S
authors: Hira
authors: Katsuhiro
authors: K
authors: Nakamura
authors: Hiroaki
authors: H
authors: Kita
authors: Satoru
authors: S
authors: Kobayashi
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D017629:Gap Junctions / Q000378:metabolism*; D005854:Germ Cells / Q000378:metabolism; D007247:Infertility, Female / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009866:Oogenesis / Q000502:physiology*; D038081:Organogenesis / Q000502:physiology; D018010:Receptors, Invertebrate Peptide / Q000378:metabolism*
chemical_list: D015820:Cadherins; D017630:Connexins; D029721:Drosophila Proteins; D018010:Receptors, Invertebrate Peptide; C120024:inx2 protein, Drosophila; C501889:shg protein, Drosophila; C066532:Egfr protein, Drosophila; D066246:ErbB Receptors