title: Adenosine deaminase-related growth factors stimulate cell proliferation in Drosophila by depleting extracellular adenosine.
abstract: We describe a protein family in Drosophila containing six adenosine deaminase-related growth factors (ADGFs), which are homologous to a mitogenic growth factor discovered in conditioned medium from cells of a different fly species, Sarcophaga. Closely related proteins have been identified in other animals, and a human homolog is implicated in the genetic disease Cat-Eye Syndrome. The two most abundantly expressed ADGFs in Drosophila larvae are ADGF-A, which is strongly expressed in the gut and lymph glands, and ADGF-D, which is mainly expressed in the fat body and brain. Recombinant ADGF-A and ADGF-D are active adenosine deaminases (ADAs), and they cause polarization and serum-independent proliferation of imaginal disk and embryonic cells in vitro. The enzymatic activity of these proteins is required for their mitogenic function, making them unique among growth factors. A culture medium prepared without adenosine, or depleted of adenosine by using bovine ADA, also stimulates proliferation of imaginal disk cells, and addition of adenosine to this medium inhibits proliferation. Thus ADGFs secreted in vivo may control tissue growth by modulating the level of extracellular adenosine.
authors.affiliation: Developmental Biology Center, University of California, Irvine, CA 92697, USA.
authors.forename: Michal
authors.initials: M
authors.lastname: Zurovec
authors.forename: Tomas
authors.initials: T
authors.lastname: Dolezal
authors.forename: Michal
authors.initials: M
authors.lastname: Gazi
authors.forename: Eva
authors.initials: E
authors.lastname: Pavlova
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bryant
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000243:Adenosine Deaminase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002455:Cell Division; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data
chemical_list: D029721:Drosophila Proteins; C447902:adenosine deaminase-related growth factor, Drosophila; D000243:Adenosine Deaminase; D000241:Adenosine