Control of stem cell self-renewal in Drosophila spermatogenesis by JAK-STAT signaling.
Stem cells, which regenerate tissue by producing differentiating cells, also produce cells that renew the stem cell population. Signals from regulatory microenvironments (niches) are thought to cause stem cells to retain self-renewing potential. However, the molecular characterization of niches remains an important goal. In Drosophila testes, germ line and somatic stem cells attach to a cluster of support cells called the hub. The hub specifically expresses Unpaired, a ligand activating the JAK-STAT (Janus kinase-signal transducer and activator of transcription) signaling cascade. Without JAK-STAT signaling, germ line stem cells differentiate but do not self-renew. Conversely, ectopic JAK-STAT signaling greatly expands both stem cell populations. We conclude that the support cells of the hub signal to adjacent stem cells by activation of the JAK-STAT pathway, thereby defining a niche for stem cell self-renewal.
Tulina
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Department of Embryology, Carnegie Institution of Washington, 115 West University Parkway, Baltimore, MD 21210, USA.
Matunis
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E
D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D002470:Cell Survival; D003285:Contractile Proteins / Q000032:analysis; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005854:Germ Cells / Q000166:cytology / Q000502:physiology*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D053612:Janus Kinases; D008024:Ligands; D008297:Male; D018613:Microscopy, Confocal; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D050791:STAT Transcription Factors; D015398:Signal Transduction; D013091:Spermatogenesis; D013093:Spermatogonia / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D013737:Testis / Q000166:cytology / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
D003285:Contractile Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006023:Glycoproteins; D019476:Insect Proteins; D008024:Ligands; D050791:STAT Transcription Factors; C105675:Stat92E protein, Drosophila; D015534:Trans-Activators; D014157:Transcription Factors; C095886:anillin; C091674:bam protein, Drosophila; C115570:upd1 protein, Drosophila; D011505:Protein-Tyrosine Kinases; D053612:Janus Kinases; C085845:hop protein, Drosophila