Molecular cloning, gene expression and characterization of the third estrogen receptor of the Nile tilapia, Oreochromis niloticus

D. S. Wang, B. Senthilkumaran, C. C. Sudhakumari, F. Sakai, M. Matsuda, T. Kobayashi, M. Yoshikuni, Y. Nagahama

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Estrogens are essential for many reproductive and non-reproductive functions. In teleosts, it is well-known that several subtypes of estrogen receptors are required for the precise action of estrogens. Present study describes the cloning of the third estrogen receptor, ER-β2, from the Nile tilapia by EST sequencing coupled microarray. The cloned ER-β2 showed 77.7% amino acid identity with the reported Atlantic croaker ER-β. Three ERs, ER-α, ER-β1 and ER-β2, from the fugu genome were also isolated to analyze their gene structures. Comparison of the intron/exon boundaries and exon numbers of fugu, tilapia, rainbow trout and zebrafish, and phylogenetic analysis of 63 ER sequences revealed that ER-β probably underwent two successive lineage-specific duplications in teleost. The former took place only in zebrafish lineage, and the latter took place in advanced teleosts without the zebrafish lineage, whereas no duplication of the ER-α gene has been detected. Tissue distribution analysis by RT-PCR revealed that tilapia ER-α and ER-β1 were expressed ubiquitously, whereas ER-β2 is expressed only in the pituitary, liver, intestine, kidney and gonads, with the highest expression in the testis and the lowest level in the ovary. Northern blot analysis detected a single transcript of about 3.4 kb in the testis but not in the ovary mRNAs. In transient transfection assays using human embryonic kidney 293 (HEK293) cells, tilapia ER-β2 showed estrodiol-17β dependent transactivation.

Original languageEnglish
Pages (from-to)255-266
Number of pages12
JournalFish Physiology and Biochemistry
Issue number2-3
Publication statusPublished - Apr 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physiology
  • Aquatic Science


Dive into the research topics of 'Molecular cloning, gene expression and characterization of the third estrogen receptor of the Nile tilapia, Oreochromis niloticus'. Together they form a unique fingerprint.

Cite this