A germline-specific gap junction protein required for survival of differentiating early germ cells.
Germ cells require intimate associations and signals from the surrounding somatic cells throughout gametogenesis. The zero population growth (zpg) locus of Drosophila encodes a germline-specific gap junction protein, Innexin 4, that is required for survival of differentiating early germ cells during gametogenesis in both sexes. Animals with a null mutation in zpg are viable but sterile and have tiny gonads. Adult zpg-null gonads contain small numbers of early germ cells, resembling stem cells or early spermatogonia or oogonia, but lack later stages of germ cell differentiation. In the male, Zpg protein localizes to the surface of spermatogonia, primarily on the sides adjacent to the somatic cyst cells. In the female, Zpg protein localizes to germ cell surfaces, both those adjacent to surrounding somatic cells and those adjacent to other germ cells. We propose that Zpg-containing gap junctional hemichannels in the germ cell plasma membrane may connect with hemichannels made of other innexin isoforms on adjacent somatic cells. Gap junctional intercellular communication via these channels may mediate passage of crucial small molecules or signals between germline and somatic support cells required for survival and differentiation of early germ cells in both sexes.
Tazuke
Salli I
SI
Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305-5329, USA. tazuke@stanford.edu
Schulz
Cordula
C
Gilboa
Lilach
L
Fogarty
Mignon
M
Mahowald
Anthony P
AP
Guichet
Antoine
A
Ephrussi
Anne
A
Wood
Cricket G
CG
Lehmann
Ruth
R
Fuller
Margaret T
MT
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D017629:Gap Junctions / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000502:physiology*
D017630:Connexins; D029721:Drosophila Proteins; C459601:Zpg protein, Drosophila