The maternal JAK/STAT pathway of Drosophila regulates embryonic dorsal-ventral patterning.
Activation of NFkappaB plays a pivotal role in many cellular processes such as inflammation, proliferation and apoptosis. In Drosophila, nuclear translocation of the NFkappaB-related transcription factor Dorsal is spatially regulated in order to subdivide the embryo into three primary dorsal-ventral (DV) domains: the ventral presumptive mesoderm, the lateral neuroectoderm and the dorsal ectoderm. Ventral activation of the Toll receptor induces degradation of the IkappaB-related inhibitor Cactus, liberating Dorsal for nuclear translocation. In addition, other pathways have been suggested to regulate Dorsal. Signaling through the maternal BMP member Decapentaplegic (Dpp) inhibits Dorsal translocation along a pathway parallel to and independent of Toll. In the present study, we show for the first time that the maternal JAK/STAT pathway also regulates embryonic DV patterning. Null alleles of loci coding for elements of the JAK/STAT pathway, hopscotch (hop), marelle (mrl) and zimp (zimp), modify zygotic expression along the DV axis. Genetic analysis suggests that the JAK kinase Hop, most similar to vertebrate JAK2, may modify signals downstream of Dpp. In addition, an activated form of Hop results in increased levels of Cactus and Dorsal proteins, modifying the Dorsal/Cactus ratio and consequently DV patterning. These results indicate that different maternal signals mediated by the Toll, BMP and JAK/STAT pathways may converge to regulate NFkappaB activity in Drosophila.
Lopes
E S S
ES
Departamento de Histologia e Embriologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Araujo
H M
HM
D000818:Animals; D019521:Body Patterning / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015151:Immunoblotting; D053613:Janus Kinase 1; D053612:Janus Kinases; D008297:Male; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D050794:STAT1 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D010750:Phosphoproteins; D050794:STAT1 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; C062236:dl protein, Drosophila; C077938:cact protein, Drosophila; D011505:Protein-Tyrosine Kinases; D053613:Janus Kinase 1; D053612:Janus Kinases; C085845:hop protein, Drosophila