The distributions of the duplicate oestrogen receptors ER-beta a and ER-beta b in the forebrain of the Atlantic croaker (Micropogonias undulatus): evidence for subfunctionalization after gene duplication.
Teleost fishes have three distinct oestrogen receptor (ER) subtypes: ER-alpha, ER-beta a (or ER-gamma) and ER-beta b. ER-beta a and ER-beta b arose from a duplication of an ancestral ER-beta gene early in the teleost lineage. Here, we describe the distribution of the three ER mRNAs in the hypothalamus and cerebellum of the Atlantic croaker to address two issues: the specific functions of multiple ERs in the neuroendocrine system and the evolution and fate of duplicated genes. ER-alpha was detected in nuclei of the preoptic area (POA) and hypothalamus previously shown to possess ER-alphas in teleosts. AcER-beta b, but not ER-beta a, labelling was detected in the magnocellular neurons of the POA, nucleus posterior tuberis, the nucleus recessus posterior and cerebellum. By contrast, acER-beta a, but not ER-beta b, was detected in the dorsal anterior parvocellular POA and suprachiasmatic nucleus. Both ER-betas were found in posterior parvocellular and ventral anterior POA nuclei, the ventral hypothalamus, and periventricular dorsal hypothalamus. The differences we observed in ER subtype mRNA distribution within well-characterized brain nuclei suggest that ER-beta a and ER-beta b have distinct functions in the neuroendocrine control of reproduction and behaviour, and provide evidence that the teleost ER-beta paralogues have partitioned functions of the ancestral ER-beta gene they shared with tetrapods.
Hawkins
M B
MB
Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373, USA. beth_hawkins@ncsu.edu
Godwin
J
J
Crews
D
D
Thomas
P
P
D000818:Animals; D047629:Estrogen Receptor beta / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005260:Female; D020869:Gene Expression Profiling; D020131:Genes, Duplicate / Q000235:genetics; D017403:In Situ Hybridization; D015336:Molecular Probe Techniques; D010473:Perciformes / Q000378:metabolism*; D016548:Prosencephalon / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D013781:Texas
D047629:Estrogen Receptor beta; D012333:RNA, Messenger