Sex-lethal facilitates the transition from germline stem cell to committed daughter cell in the Drosophila ovary.
In Drosophila, the female-specific SEX-LETHAL (SXL) protein is required for oogenesis, but how Sxl interfaces with the genetic circuitry controlling oogenesis remains unknown. Here we use an allele of sans fille (snf) that specifically eliminates SXL protein in germ cells to carry out a detailed genetic and cell biological analysis of the resulting ovarian tumor phenotype. We find that tumor growth requires both Cyclin B and zero population growth, demonstrating that these mutant cells retain at least some of the essential growth-control mechanisms used by wild-type germ cells. Using a series of molecular markers, we establish that while the tumor often contains at least one apparently bona fide germline stem cell, the majority of cells exhibit an intermediate fate between a stem cell and its daughter cell fated to differentiate. In addition, snf tumors misexpress a select group of testis-enriched markers, which, remarkably, are also misexpressed in ovarian tumors that arise from the loss of bag of marbles (bam). Results of genetic epistasis experiments further reveal that bam's differentiation-promoting function depends on Sxl. Together these data demonstrate a novel role for Sxl in the lineage progression from stem cell to committed daughter cell and suggest a model in which Sxl partners with bam to facilitate this transition.
Chau
Johnnie
J
Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4955, USA.
Kulnane
Laura Shapiro
LS
Salz
Helen K
HK
D000818:Animals; D030801:Animals, Genetically Modified; D015153:Blotting, Western; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D005854:Germ Cells / Q000502:physiology*; D008297:Male; D009866:Oogenesis / Q000502:physiology; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010053:Ovary / Q000166:cytology* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000502:physiology*; D013737:Testis / Q000502:physiology
C503698:CycB protein, Drosophila; D019926:Cyclin B; D029721:Drosophila Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C067777:Sxl protein, Drosophila; C091674:bam protein, Drosophila