title: Expression of estrogen receptor beta messenger RNA variant in breast cancer.
abstract: Estrogen receptor (ER) beta is expressed in a number of tissues, including the breast. We have recently shown that ER-beta mRNA is regulated by estradiol (E2) and that antiestrogens antagonize E2 induction of ER-beta mRNA. Here, we identify by reverse transcription-PCR and by the RNase protection assay a mRNA coding for a variant of ER-beta that is coexpressed with wild-type ER-beta in the ER-alpha-negative, estrogen-independent breast cancer cell line MDA-MB-231 and in malignant breast tumor specimens. In contrast, this variant was not seen in the tested normal breast tissue. Sequence analysis of the ER-beta variant PCR product revealed the absence of 139 bp within the hormone-binding domain. This ER-beta deletion corresponds precisely to the entire exon 5 of ER-alpha. The ER-beta variant protein is predicted to lack part of the hormone-binding domain and may bind E2 with lower affinity than the wild-type ER-beta protein.
authors.affiliation: Lawrence Berkeley National Laboratory, University of California, Berkeley 94710, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Vladusic
authors.forename: A E
authors.initials: AE
authors.lastname: Hornby
authors.forename: F K
authors.initials: FK
authors.lastname: Guerra-Vladusic
authors.forename: R
authors.initials: R
authors.lastname: Lupu
mesh_terms: D001483:Base Sequence; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D047629:Estrogen Receptor beta; D005260:Female; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009940:Organoids / Q000378:metabolism / Q000473:pathology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D012334:RNA, Neoplasm / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D017931:DNA Primers; D047629:Estrogen Receptor beta; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen