The shut-down gene of Drosophila melanogaster encodes a novel FK506-binding protein essential for the formation of germline cysts during oogenesis.
In Drosophila melanogaster, the process of oogenesis is initiated with the asymmetric division of a germline stem cell. This division results in the self-renewal of the stem cell and the generation of a daughter cell that undergoes four successive mitotic divisions to produce a germline cyst of 16 cells. Here, we show that shut-down is essential for the normal function of the germline stem cells. Analysis of weak loss-of-function alleles confirms that shut-down is also required at later stages of oogenesis. Clonal analysis indicates that shut-down functions autonomously in the germline. Using a positional cloning approach, we have isolated the shut-down gene. Consistent with its function, the RNA and protein are strongly expressed in the germline stem cells and in 16-cell cysts. The RNA is also present in the germ cells throughout embryogenesis. shut-down encodes a novel Drosophila protein similar to the heat-shock protein-binding immunophilins. Like immunophilins, Shut-down contains an FK506-binding protein domain and a tetratricopeptide repeat. In plants, high-molecular-weight immunophilins have been shown to regulate cell divisions in the root meristem in response to extracellular signals. Our results suggest that shut-down may regulate germ cell divisions in the germarium.
Munn
K
K
Waksman Institute, Rutgers University, Piscataway, New Jersey 08854, USA.
Steward
R
R
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004331:Drosophila melanogaster / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D017344:Genes, Insect; D020104:Immunophilins / Q000235:genetics; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D022021:Tacrolimus Binding Proteins
D018076:DNA, Complementary; D019476:Insect Proteins; D022021:Tacrolimus Binding Proteins; D020104:Immunophilins