The position and function of the Notch-mediated eye growth organizer: the roles of JAK/STAT and four-jointed.
In many animal systems, the local activation of patterning signals in spatially confined regions (organizers) is crucial for promoting the growth of developing organs. Nevertheless, how organizers are set up and how their activity influences global organ growth remains poorly understood. In the Drosophila eye, local Notch activation establishes a conserved dorsal-ventral organizer that promotes growth. The dorsal selector Iroquois complex defines the position of the organizer at the mid-first instar, and through its ligand, unpaired, the Janus kinase (JAK)/signal transducers and activator of transcription (STAT) pathway is thought to mediate global growth downstream of the organizer. However, here we show that the unpaired/JAK/STAT pathway is actually a fundamental element in the spatial control of the organizer, upstream from Notch activation. Furthermore, we identify four-jointed, a target of the Fat and Hippo tumour-suppressor pathways, as a mediator of the growth controlled by the organizer. These findings redefine the process of organizer formation and function, and they identify four-jointed as a regulatory node, integrating multiple growth-control pathways.
Gutierrez-Aviño
Francisco Jose
FJ
Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Campus de Sant Joan, Avd Santiago Ramon y Cajal s/n Crta. Alicante-Valencia km 87, Alicante, Apartado 18, E-03550, San Juan de Alicante, Spain.
Ferres-Marco
Dolors
D
Dominguez
Maria
M
D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism; D053612:Janus Kinases / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction; D051155:Wnt1 Protein / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; D053823:Hedgehog Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; D050791:STAT Transcription Factors; D051155:Wnt1 Protein; C074622:wg protein, Drosophila; C077245:hh protein, Drosophila; D053612:Janus Kinases