Abstract
The molecular mechanism underlying the renal expression localization of the thiazide-sensitive Na-Cl cotransporter (TSC) gene was studied. The TSC gene was localized to chromosome 19p12-14. In cultured cells, tissue-specific transcription activity of the 5'-flanking region of the rat rTSC gene (5'FL/rTSC) was demonstrated, and the major promoter region was located between position -580 and -141. To further examine the tissue-specific transcription, transgenic rats harboring the 5'FL/rTSC fused upstream of the LacZ gene were generated. Immunohistochemical analysis clearly showed that LacZ gene expression was co-localized to distal convoluted tubules (DCT) with TSC, indicating that the 5'FL/rTSC regulates the renal tubule-specific TSC expression. Because a transcription factor, HFH-3 (hepatocyte nuclear factor-3/folk head homologue-3), had also been localized to DCT, a possible role of the putative cis-acting element (HFH-3/rTSC, -400/-387 position) for HFH-3 binding in the tissue-specific transcription was examined. Deletion and mutation analyses suggested that transcription of the HFH-3/rTSC was actually responsive to HFH-3, and electrophoretic mobility shift assay showed a direct binding of in vitro synthesized HFH-3 to the HFH-3/rTSC. In conclusion, the rTSC gene is localized to rat chromosome 19p12--24. The transcription regulatory region of the TSC gene confers DCT-specific gene expression. DCT-specific transcription factor HFH-3 may be involved in the renal tubule-specific transcription of TSC gene.
Highlights
The nucleotide sequence(s) reported in this paper has been submitted to the GenBankTM/EBI Data Bank with accession number(s) AB024534
The protein-DNA complex was kept unchanged with an excess of oligonucleotides of mHFH-3/rTSC as a competitor. These results indicate that HFH-3/rTSC is bound by HFH-3 and the binding is sequence-specific
The rTSC gene was shown to be localized to 19p12–14 by FISH
Summary
The nucleotide sequence(s) reported in this paper has been submitted to the GenBankTM/EBI Data Bank with accession number(s) AB024534. TSC mRNA expression has been shown to be localized to the distal convoluted tubule (DCT) in the kidney by in situ hybridization histochemistry [7, 8] as well as reverse transcription and polymerase chain reaction (RT-PCR) with microdissected nephron segments [9]. Members of the family have been shown to be involved in tissue- or cell-specific gene expression, as well as cellular differentiation during embryonic development [14, 15]. We studied the tissue-specific expression of the TSC gene in terms of gene transcription by an in vivo as well as in vitro experiments. We generated transgenic rats harboring the 5ЈFL/rTSC fused upstream of the LacZ gene to examine the tissue-specific transcription of 5ЈFL/rTSC. Immunohistochemical analysis clearly demonstrated that LacZ expression was localized to DCT in the transgenic rat kidney, indicating that the 5ЈFL/rTSC regulates the DCT-specific TSC localization in vivo. HFH-3 may be involved at least in part in the DCTspecific expression of TSC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
