Rat Parathyroid Hormone-Like Peptide: Comparison with the Human Homologue and Expression in Malignant and Normal Tissue

Abstract

A rat Leydig cell tumor cDNA library was screened with a 32P-labeled genomic restriction fragment encoding human PTH-like peptide (hPLP), and three cDNA clones were isolated. The largest cDNA insert contained 1146 nucleotides. The cloned cDNA encodes a 177-amino acid protein consisting of a predicted 36-amino acid leader sequence and a 141-amino acid mature peptide in which 9 of 13 amino-terminal residues are identical to rat PTH (rPTH). Comparison of rPLP with hPLP reveals marked conservation of both the nucleotide and amino acid sequences through the prepro, amino-terminal, and midregion portions of the molecules. There is also striking conservation of the 3' noncoding regions of rPLP and hPLP mRNAs, both of which contain AU-rich repeated sequences that may affect mRNA stability. A single species of mRNA of approximately 1.4-kilobases was identified in the rat Leydig cell tumor and in normal rat stomach. Southern blot analysis is consistent with the presence of a single copy of the rPLP gene per haploid genome, and there is no major rearrangement or amplification of the rPLP gene in DNA isolated from the tumor per se. The results demonstrate the presence of a single gene transcript in a rat model of malignancy associated with hypercalcemia which encodes a peptide homologous to hPLP, document the marked interspecies sequence conservation that exists in major functional domains of the mRNAs and peptides, and show the expression of mRNA encoding rPLP in normal stomach as well as in neoplastic rat tissue.

Preproparathyroid Hormone-related Protein, a Secreted Peptide, Is a Substrate for the Ubiquitin Proteolytic System

“…Plasmid Construction-All PTHrP constructs were derived from the cDNA encoding rat prepro-PTHrP (PLPm10) (25). For transfection studies, prepro-PTHrP was expressed with a histidine tag at the COOH terminus using the mammalian expression vector pRC/CMV (Invitrogen).…”

Global amplification polymerase chain reaction reveals novel transitional stages during osteoprogenitor differentiation

“…Mouse FGF-R1 [ (Mansukhani et al, 1990) a gift of C. Basilico, New York, NY] was a 400 bp cDNA HincII-PstI fragment. Rat PTHrP [ (Yasuda et al, 1989) …”

Regulation of parathyroid hormone-like peptide in cultured normal human keratinocytes. Effect of growth factors and 1,25 dihydroxyvitamin D3 on gene expression and secretion.

“…87:884-893.) Key words: calcium * epidermal growth factorkeratinocyte differentiation * transient transfection Messenger RNAs and the gene encoding parathyroid hormone (PTH)-like peptide (PLP),' which was initially isolated from human tumors associated with hypercalcemia (1-3), have now been cloned and characterized in the human (4-9) and rat (10)(11)(12). PLP mimics many of the biological actions of PTH (13), but is also likely to have its own functions which are separate from its PTH-like effects.…”

“…Nevertheless, multiple PLP transcripts may not al- Our transient transfection analysis demonstrated that both GF and serum enhanced PLP promoter activity indicating that at least part of the stimulatory effect of these modulators on PLP production in keratinocytes resides at the level of augmenting gene expression. The difference in the apparent kinetics of the effect of growth factors and serum on enhancing endogenous PLP production by keratinocytes and on increasing hGH release during transient transfection assays may re- (11).…”