Cloning of bovine parathyroid hormone-related protein (PTHrP) cDNA and expression of PTHrP mRNA in the bovine mammary gland

Abstract

Parathyroid hormone-related protein (PTHrP) produced by the mammary gland has been postulated to have multiple functions in both the mother and neonate. In humans, alternative 3 -mRNA splicing and endoproteolytic processing result in multiple bioactive PTHrP peptides. Multiple PTHrP peptides also have been reported in bovine milk. To investigate the source of molecular heterogeneity of PTHrP in bovine milk, bovine PTHrP was cloned from a bovine brain cDNA library, sequenced and used to characterize the mammary PTHrP transcript. A 1065 bp clone (bP1) for bovine PTHrP was isolated from a brain cDNA library. The bP1 clone contained the entire coding sequence of PTHrP and 61 and 473 nucleotides of the 5 -and 3 -untranslated regions (UTRs) respectively. The predicted amino acid sequence of bovine PTHrP was 72-92% homologous to the sequences of chicken, rat, mouse, human, and canine PTHrP with the highest sequence divergence present in the C-terminal region of the peptide. The 5 -and 3 -UTRs of bovine brain PTHrP have a high degree of homology to exons 4 and 9 of human PTHrP respectively. PTHrP was expressed as a single 1200 nucleotide mRNA transcript in lactating bovine mammary tissue. RT-PCR using region-specific oligonucleotide primers derived from bP1 demonstrated that PTHrP mRNA transcripts in bovine brain and lactating mammary gland utilize the same 5 -and 3 -UTRs. Expression of PTHrP mRNA was localized to secretory and ductular epithelial cells within the lactating mammary gland, as detected using in situ hybridization. Expression of PTHrP mRNA was demonstrated in the mammary gland during late pregnancy and throughout lactation in cows.

Plasma parathyroid hormone-related peptide and bone metabolism in periparturient dairy cows

“…The concentration of PTHrP was determined in a competitive enzyme immunoassay, using a commercial kit pTH-Related Peptide (1-34) (human, rat) (Peninsula Laboratories, Inc., San Carlos, CA, USA). Although this kit was developed to measure human and rat PTHrP (1-34), we used it because the predicted amino acid sequence of bovine 1-34 PTHrP is identical to human and rat PTHrP (1-34) (Wojcik et al, 1998). The concentration of PTH was determined using the commercial kit Intact PTH (Parathyroid Hormone) ELISA (Biomerica, Newport Beach, CA, USA).…”

Expression of PTHrP and the PTH/PTHrP receptor in growing red deer antler

“…The sequence is shown in Fig. 2 as a BlastP comparison with the most similar sequencedthat of bovine PTHrP (Wojcik et al, 1998).…”

Expression of Parathyroid Hormone-Related Protein (PTHrP) mRNA in Mammary Gland of Periparturient Cows

“…In the lactating mammary gland in cows, PTHrP was considered to be synthesized at least in alveolar epithelial cells and to be secreted into the lumen, although Kramer et al [4] and Grone et al [2] reported that PTHrP was detected in alveolar epithelial cells and also in duct epithelial cells and myoepithelial cells. The expression of PTHrP mRNA was reported to be detected in mammary gland [14]. In this study, the relative level of PTHrP mRNA in the lactating mammary gland was significantly higher than that in the non-lactating cows.…”