Budhead, a fork head/HNF-3 homologue, is expressed during axis formation and head specification in hydra.
Accumulating evidence indicates that a common set of genes and mechanisms regulates the developmental processes of a variety of triploblastic organisms despite large variation in their body plans. To what extent these same genes and mechanisms are also conserved among diploblasts, which arose earlier in metazoan evolution, is unclear. We have characterized a hydra homologue of the fork head/HNF-3 class of winged-helix proteins, termed budhead, whose expression patterns suggest a role(s) similar to that found in vertebrates. The vertebrate HNF-3 beta homologues are expressed early in embryogenesis in regions that have organizer properties, and later they have several roles, among them an important role in rostral head formation. In the adult hydra, where axial patterning processes are continuously active, budhead is expressed in the upper part of the head, which has organizer properties. It is also expressed during the formation of a new axis as part of the development of a bud, hydra's asexual form of reproduction. Expression during later stages of budding, during head regeneration and the formation of ectopic heads, indicates a role in head formation. It is likely that budhead plays a critical role in head as well as axis formation in hydra.
Martinez
D E
DE
Developmental Biology Center, University of California, Irvine 92697, USA.
Dirksen
M L
ML
Bode
P M
PM
Jamrich
M
M
Steele
R E
RE
Bode
H R
HR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D051542:Hepatocyte Nuclear Factor 3-beta; D006829:Hydra / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology; D010802:Phylogeny; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012038:Regeneration; D012100:Reproduction, Asexual; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011506:Proteins; D014157:Transcription Factors; C110149:budhead protein, Hydra attenuata; D051542:Hepatocyte Nuclear Factor 3-beta