Hirata Shuji, Shoda Tomoko, Kato Junzo, Hoshi Kazuhiko
Department of Obstetrics and Gynecology, Faculty of Medicine, University of Yamanashi, Shimokato 1110, Tamaho, Nakakoma, Yamanashi 409-3898, Japan.
J Steroid Biochem Mol Biol. 2002 Dec;83(1-5):25-30. doi: 10.1016/s0960-0760(02)00255-8.
In our recent reports, the novel isoform cDNAs of the ER alpha (ER alpha isoform S cDNA), ER beta (ER beta isoform M cDNA) and PR (PR isoform S and PR isoform T cDNAs) have been identified. These isoform cDNAs contained the previously unidentified 5'-sequences on exons 4-8 (ER alpha isoform S cDNA), exons 5-8 (ER beta isoform M cDNA) or exons 4-8 (PR isoform S and PR isoform T cDNAs). The genomic DNA analysis revealed that the 5'-sequences were derived from the novel independent exons, the ER alpha exon S, ER beta exon M, PR exon S and PR exon T, respectively. Furthermore, the existence of the novel variant mRNA, termed the i45 PR mRNA variant, with the insertion of the previously unidentified exons, termed the exons i45a and i45b, has been demonstrated by the reverse transcription-polymerase chain reaction on the RNA of the human uterine endometrium. From these results, we have concluded that the genes for the human female sex steroid hormone receptors contain the novel intronic exons, that the novel isoform mRNAs are transcribed using the intronic exon and exons 4-8 (or exons 5-8) of the gene, and that the novel variant mRNA is generated by the insertion of the intronic exons in the PR. In the present communication, our recent data along with others on the novel isoform/variant mRNAs for the human female sex steroid hormone receptors will be summarized.
