A head-activator binding protein is present in hydra in a soluble and a membrane-anchored form.
The neuropeptide head activator plays an important role for proliferation and determination of stem cells in hydra. By affinity chromatography a 200 kDa head-activator binding protein, HAB, was isolated from the multiheaded mutant of Chlorohydra viridissima. Partial amino acid sequences were used to clone the HAB cDNA which coded for a receptor with a unique alignment of extracellular modules, a transmembrane domain, and a short carboxy-terminal cytoplasmic tail. A mammalian HAB homologue with identical alignment of these modules is expressed early in brain development. Specific antibodies revealed the presence of HAB in hydra as a transmembrane receptor, but also as secreted protein, both capable of binding head activator. Secretion of HAB during regeneration and expression in regions of high determination potential hint at a role for HAB in regulating the concentration and range of action of head activator.
Hampe
W
W
Center for Molecular Neurobiology, University of Hamburg, Martinistr. 52, D-20246 Hamburg, Germany. hampe@uke.uni-hamburg.de
Urny
J
J
Franke
I
I
Hoffmeister-Ullerich
S A
SA
Herrmann
D
D
Petersen
C M
CM
Lohmann
J
J
Schaller
H C
HC
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004475:Ectoderm; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D006829:Hydra / Q000196:embryology / Q000502:physiology*; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009479:Neuropeptides / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D018000:Receptors, Peptide / Q000378:metabolism*; D012038:Regeneration; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D008565:Membrane Proteins; D009479:Neuropeptides; D018000:Receptors, Peptide; C069362:head activator receptor, Hydra; C032522:head activator peptide; D011761:Pyrrolidonecarboxylic Acid