William L. Gale
Xiaotian Chang
David Langenau
Reynaldo Patino
Alec G. Maule
Llewellyn D. Densmore
Zhenfang Xia
2000
<div class="abstract svAbstract " data-etype="ab">
<p id="simple-para0005"><span>An </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Estrogen">estrogen</a><span> receptor β (ERβ) cDNA fragment was amplified by </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Reverse_transcription_polymerase_chain_reaction">RT-PCR</a><span> of total </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/RNA">RNA</a><span>extracted from liver and ovary of immature channel catfish. This cDNA fragment was used to screen an ovarian </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/CDNA_library">cDNA library</a><span> 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 </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Phylogenetics">phylogenetic</a><span> 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 </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Estrogen_receptor">ER subtypes</a><span>, α and β. Within each subtype, and in accordance with established </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Phylogenetics">phylogenetic relationships</a><span>, teleost and tetrapod ER were monophyletic confirming the results of a previous analysis (Z. Xia</span><i>et al</i><span>., 1999, </span><i>Gen. Comp. Endocrinol</i><span>. </span><span class="boldFont">113,</span><span> 360–368). Extracts of </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/COS_cells">COS-7</a><span> cells </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Transfection">transfected</a><span>with channel catfish ERβ cDNA bound estrogen with high affinity (</span><i>K</i><sub>d</sub><span> = 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 </span><a class="linkText" href="http://topics.sciencedirect.com/topics/page/Ligand_(biochemistry)">ligand-binding</a><span> 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.</span></p>
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application/pdf
10.1006/gcen.1999.7447
en
Elsevier
Phylogenetic sequence analysis, recombinant expression, and tissue distribution of a channel catfish estrogen receptor beta
article