title: Expression of heterogeneous nuclear ribonucleoproteins A2 and b1 in the thyroid follicular cells.
abstract: Several proteins implicated in hormonogenesis of the thyroid have alternatively spliced isoforms. Alternative splicing of pre-mRNA is considered to be important to regulate the hormonal activity. Heterogeneous nuclear ribonucleoproteins (hnRNP) A2 and B1 are two of the abundant nuclear RNA-binding proteins involved in alternative splicing. We examined the expression of hnRNP A2 and B1 in the thyroid, paying particular attention to the relationship between their function and the cellular morphology. B1 was expressed more frequently in cuboidal follicular cells that are hormonally active than in flat follicular cells in normal thyroid, although A2 expression showed no significant difference in two cell types. In Graves' disease, the patients who had high serum levels of triiodothyronine and thyroxine showed significantly increased expression of B1. B1 expression did not differ significantly between normal thyroids and thyroid neoplasms, except undifferentiated (anaplastic) carcinoma. Conclusively, B1 expression varied in relation to hormonal activity in thyroid follicular cells. B1 protein is a good immunohistological marker to detect hormonal activity of follicular cells, and may provide a key to elucidate the splicing mechanisms involved in thyroid hormonogenesis.
authors.affiliation: Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Yano
authors.forename: Wenwen
authors.initials: W
authors.lastname: Wu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamma
authors.forename: Masachika
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Hisato
authors.initials: H
authors.lastname: Hara
authors.forename: Tohru
authors.initials: T
authors.lastname: Yashiro
authors.forename: Ei
authors.initials: E
authors.lastname: Ueno
authors.forename: Masanao
authors.initials: M
authors.lastname: Miwa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Aiyoshi
mesh_terms: D017398:Alternative Splicing; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D006111:Graves Disease / Q000378:metabolism* / Q000473:pathology; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D013961:Thyroid Gland / Q000033:anatomy & histology / Q000378:metabolism* / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; C439768:hnRNP A2