TY - JOUR
T1 - Phylogenetic sequence analysis, recombinant expression, and tissue distribution of a channel catfish estrogen receptor β
AU - Xia, Zhenfang
AU - Gale, William L.
AU - Chang, Xiaotian
AU - Langenau, David
AU - Patiño, Reynaldo
AU - Maule, Alec G.
AU - Densmore, Llewellyn D.
N1 - Funding Information:
The Texas Cooperative Fish & Wildlife Research Unit is jointly supported by the U.S. Geological Survey, Texas Tech University, Texas Parks & Wildlife Department, and The Wildlife Management Institute. This project was funded by U.S. Department of Agriculture Grant 97–35203–4805.
PY - 2000/4
Y1 - 2000/4
N2 - An estrogen receptor β (ERβ) cDNA fragment was amplified by RT-PCR of total RNA extracted from liver and ovary of immature channel catfish. This cDNA fragment was used to screen an ovarian cDNA library made from an immature female fish. A clone was obtained that contained an open reading frame encoding a 575-amino-acid protein with a deduced molecular weight of 63.9 kDa. Maximum parsimony and Neighbor Joining analyses were used to generate a phylogenetic classification of channel catfish ERβ on the basis of 25 full-length teleost and tetrapod ER sequences. The consensus tree obtained indicated the existence of two major vertebrate ER subtypes, α and β. Within each subtype, and in accordance with established phylogenetic relationships, teleost and tetrapod ER were monophyletic confirming the results of a previous analysis (Z. Xia et al., 1999, Gen. Comp. Endocrinol. 113,360-368). Extracts of COS-7 cells transfected with channel catfish ERβ cDNA bound estrogen with high affinity (K(d) = 0.21 nM) and specificity. The affinity of channel catfish ERβ for estrogen was higher than previously reported for channel catfish ERα. As determined by qualitative RT-PCR, the tissue distributions of ERα and ERβ were similar but not identical. Both ER subtypes were present in ovary and testis. ERα was found in all other tissues examined from juvenile and mature fish of both sexes. ERβ was also found in most tissues except, in most cases, whole blood and head kidney. Interestingly, the pattern of expression of ER subtypes in head kidney always corresponded to the pattern in whole blood. In conclusion, we isolated a channel catfish ERβ with ligand-binding affinity and tissue expression patterns different from ERα. Also, we confirmed the validity of our previously proposed general classification scheme for vertebrate ER into α and β subtypes and within each subtype, into teleost and tetrapod clades. (C) 2000 Academic Press.
AB - An estrogen receptor β (ERβ) cDNA fragment was amplified by RT-PCR of total RNA extracted from liver and ovary of immature channel catfish. This cDNA fragment was used to screen an ovarian cDNA library made from an immature female fish. A clone was obtained that contained an open reading frame encoding a 575-amino-acid protein with a deduced molecular weight of 63.9 kDa. Maximum parsimony and Neighbor Joining analyses were used to generate a phylogenetic classification of channel catfish ERβ on the basis of 25 full-length teleost and tetrapod ER sequences. The consensus tree obtained indicated the existence of two major vertebrate ER subtypes, α and β. Within each subtype, and in accordance with established phylogenetic relationships, teleost and tetrapod ER were monophyletic confirming the results of a previous analysis (Z. Xia et al., 1999, Gen. Comp. Endocrinol. 113,360-368). Extracts of COS-7 cells transfected with channel catfish ERβ cDNA bound estrogen with high affinity (K(d) = 0.21 nM) and specificity. The affinity of channel catfish ERβ for estrogen was higher than previously reported for channel catfish ERα. As determined by qualitative RT-PCR, the tissue distributions of ERα and ERβ were similar but not identical. Both ER subtypes were present in ovary and testis. ERα was found in all other tissues examined from juvenile and mature fish of both sexes. ERβ was also found in most tissues except, in most cases, whole blood and head kidney. Interestingly, the pattern of expression of ER subtypes in head kidney always corresponded to the pattern in whole blood. In conclusion, we isolated a channel catfish ERβ with ligand-binding affinity and tissue expression patterns different from ERα. Also, we confirmed the validity of our previously proposed general classification scheme for vertebrate ER into α and β subtypes and within each subtype, into teleost and tetrapod clades. (C) 2000 Academic Press.
KW - Channel catfish
KW - Classification
KW - Cloning
KW - Estrogen receptor β
KW - Fish
KW - Recombinant expression
KW - Sequence
KW - Teleost
KW - Tissue distribution
UR - http://www.scopus.com/inward/record.url?scp=0034090269&partnerID=8YFLogxK
U2 - 10.1006/gcen.1999.7447
DO - 10.1006/gcen.1999.7447
M3 - Article
C2 - 10753576
AN - SCOPUS:0034090269
SN - 0016-6480
VL - 118
SP - 139
EP - 149
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 1
ER -