Drosophila unpaired encodes a secreted protein that activates the JAK signaling pathway.
In vertebrates, many cytokines and growth factors have been identified as activators of the JAK/STAT signaling pathway. In Drosophila, JAK and STAT molecules have been isolated, but no ligands or receptors capable of activating the pathway have been described. We have characterized the unpaired (upd) gene, which displays the same distinctive embryonic mutant defects as mutations in the Drosophila JAK (hopscotch) and STAT (stat92E) genes. Upd is a secreted protein, associated with the extracellular matrix, that activates the JAK pathway. We propose that Upd is a ligand that relies on JAK signaling to stimulate transcription of pair-rule genes in a segmentally restricted manner in the early Drosophila embryo.
Harrison
D A
DA
Department of Genetics, Boston, Massachusetts 02115 USA. DougH@pop.uky.edu
McCoon
P E
PE
Binari
R
R
Gilman
M
M
Perrimon
N
N
D000595:Amino Acid Sequence; D000818:Animals; D020029:Base Pairing; D001483:Base Sequence; D016207:Cytokines / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D053612:Janus Kinases; D008969:Molecular Sequence Data; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism* / Q000502:physiology; D050791:STAT Transcription Factors; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D016207:Cytokines; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D019476:Insect Proteins; D050791:STAT Transcription Factors; C105675:Stat92E protein, Drosophila; D015534:Trans-Activators; D014157:Transcription Factors; C096359:sr protein, Drosophila; C115570:upd1 protein, Drosophila; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D053612:Janus Kinases; C085845:hop protein, Drosophila