Parathyroid hormone/parathyroid hormone related peptide receptor gene transcripts are expressed from tissue-specific and ubiquitous promoters

Abstract

Parathyroid hormone (PTH) and PTH related peptide (PTHrP) stimulate diverse physiological responses in a number of tissues by binding to the same receptor. We have previously cloned the gene encoding the mouse PTH/PTHrP receptor (PTHR), and have identified a promoter region. The first exon transcribed from this promoter contains untranslated sequence and is followed by an exon encoding signal sequence and the first amino acids of the mature polypeptide. We have now identified and characterized a second promoter region, located > 3 kb upstream of the original. Four partial cDNA clones, amplified from mouse kidney RNA by reverse transcription followed by the polymerase chain reaction, contain sequence corresponding to two previously unidentified exons composed of untranslated sequence. The second (3') of the two exons is spliced to the previously identified signal sequence exon. These cDNAs are highly homologous to the 5' end of a cDNA isolated from human kidney, strongly suggesting that the promoter region is conserved between mouse and humans. RNase protection and primer extension experiments have identified several transcriptional start sites extending over a region of approximately 100 bp. Unlike the previously identified promoter, this promoter is not (G+C)-rich. It lacks a consensus TATA element, but does contain a consensus CCAAT box. We have determined the expression patterns of both promoters by RNase protection with total and poly A+ RNA from several mouse tissues. The newly identified promoter is highly tissue specific, being strongly active in kidney and weakly active in liver, but not expressed in the other tissues studied. The previously identified (G+C)-rich promoter is expressed in all tissues studied. This indicates that the PTHR gene expression is controlled by regulatory signals specific to kidney and liver, as well as signals functioning in a wide variety of cell types. These results may provide insight into certain defects in PTH signalling found in humans.

Oxytocin receptor gene expression in rat mammary gland: structural characterization and regulation

“…OTR mRNA were determined semi-quantitatively using an RT-PCR assay described previously Differential selection of transcriptional initiation sites represents an alternative mechanisms that could underlie the production of differentially sized mRNAs. Differential transcriptional initiation resulting in differential promoter usage has indeed been found to occur in genes that encode members of the G-protein coupled receptor family and include the PTH/PTHRP receptor gene (McCuaig et al 1995) and the -adrenergic receptor gene (Gao & Kunos 1994). The results from our primer extension studies do not support the hypothesis that such a mechanism underlies the tissue-specific differential regulation of the OTR gene, since we found that OTR transcription initiates at exactly the same positions in mammary gland and uterine tissues.…”

Vitamin D3 differentially regulates parathyroid hormone/parathyroid hormone-related peptide receptor expression in bone and cartilage

“…The PTHR is widely expressed, with the highest levels being found in kidney and bone (33). The mouse gene encoding the PTHR is composed of at least 17 exons, and its expression is regulated by at least two promoters (34,35), which give rise to two transcripts that differ in their 5′ untranslated sequences, but not in their coding regions. Transcripts from the upstream mouse promoter (P1) contain sequences derived from two 5′ untranslated region exons, U1 and U2, and are highly expressed in kidney and weakly expressed in liver.…”

Functional importance of Myc-associated zinc finger protein for the human parathyroid hormone (PTH)/PTH-related peptide receptor-1 P2 promoter constitutive activity

“…Indeed, the P2 promoter sequence presents several properties which are compatible with a broad expression pattern. No TATA box consensus sequence is detected, and it presents a high G+C content, a situation which resembles that found for most housekeeping genes (McCuaig et al 1995). In addition, potential/putative binding sites for Sp1 and MAZ (Myc-associated zinc finger protein), two broadly active transcription factors known to bind to G+C-rich sequences (Parks & Shenk 1996, Izzo et al 1999, Song et al 2001, are present in the human and mouse P2 sequence (Bettoun et al 1997, Minagawa et al 2000.…”

“…Transcripts derived from P2 promoter can be detected in humans and in rodents in numerous fetal and adult tissues, including cartilage and bone (Bettoun et al 1998, Amizuka et al 1999, Minagawa et al 2000. Although tissue-and species-specific PTHR1 promoter activity is described, the genes encoding for PTHR1 in different species are highly homologous (Kong et al 1994), and the broad PTHR1 expression is mostly attributed to P2 activity (McCuaig et al 1995. Indeed, the P2 promoter sequence presents several properties which are compatible with a broad expression pattern.…”