Two forms of the prolactin receptor messenger ribonucleic acid are Present in ovine fetal liver and adult ovary

Abstract

Previous binding studies indicated that there is little to no specific prolactin binding in ovine fetal liver and adult ovary. Therefore, we sought to determine if ovine prolactin receptor (PRLR) mRNA is present in those tissues. Primers were designed from the bovine PRLR cDNA sequence for use in reverse transcriptase-polymerase chain reaction (RT-PCR). RT-PCR analysis of ovine fetal liver total cellular RNA (tcRNA) isolated from days 60, 90, 105, 120 and 135 of gestation, and luteal tcRNA isolated from days 3, 7, 10, 13 and 16 of the estrous cycle revealed that PRLR mRNA was present in these tissues. However, two RT-PCR products were generated from both tissues. The two RT-PCR products did not differ between the two tissue sources in sequence, and were designated oPRLR-1 and oPRLR-2. Ovine PRLR-1 is 513 bp in length and is 96.4% identical to the bovine cDNA. Ovine PRLR-2 is identical to oPRLR-1 until nucleotide (nt) 420 at which point a 39 bp insertion occurs. This insertion occurs between Homology Boxes 1 and 2 within the cytoplasmic domain of the receptor, resulting in an 11 amino acid divergent sequence, followed by two stop codons. Ribonuclease-protection assay revealed that oPRLR-1 mRNA is the most abundant in these tissues. Our data indicate that two forms of oPRLR mRNA are Present in fetal liver and adult ovary, and that one form (oPRLR-2) is predicted to encode a truncated PRLR.

Expression of the prolactin receptor (tiPRL-R) gene in tilapia Oreochromis niloticus: tissue distribution and cellular localization in osmoregulatory organs

“…In vertebrates, whilst the long form of PRL-R has been reported in all the species studied so far, including birds and fish, other PRL-R forms exhibiting short cytoplasmic domains have only been identified in mammals (Anthony et al 1995, Hu et al 1998, Jabbour et al 1998. Each PRL-R form is encoded by one or several specific transcripts, and a cDNA probe spanning the extracellular domain allows the detection of all the transcripts encoding both long and short forms by Northern blot analysis (Kelly et al 1991, Cassy et al 1998, Jabbour et al 1998.…”

“…The wide tissue distribution of the PRL-R reported at the RNA as well as the protein level is in agreement with the broad spectrum of PRL functions (Bole-Feysot et al 1998). Different PRL-R isoforms, which differ primarily by the lengths of their cytoplasmic domains, have been identified in rodents and mammals (Kelly et al 1991, Anthony et al 1995, Jabbour et al 1998. Multiple PRL-R transcripts corresponding to either PRL-R isoform have been described in mammals and are associated to a complex pattern of expression and regulation (Hu et al 1998).…”

Functional Characterization of the Intermediate Isoform of the Human Prolactin Receptor

“…The Human PRLr Intermediate Isoform Shows Variable Tissue Expression-Previous studies have shown that the number of isoforms and levels of PRLr expression vary between tissues in several different species (28,30,31,48). To determine if the intermediate isoform shows the same variability in expression between tissues, a dot blot containing mRNA isolated from a variety of human tissues were probed with cDNA fragments specific for either the long or intermediate isoforms (Fig.…”

“…The Box 2 domain is hydrophobic and acidic, and its signaling function is largely uncharacterized. Several isoforms of the PRLr have been identified in both mammals (25)(26)(27)(28)(29)(30)(31) and birds (32)(33)(34). The most well characterized isoforms are those found in the rat: the short form (45 kDa) (35), long form (80 -85 kDa) (36), and a mutant intermediate form found on the PRL-dependent rat T cell lymphoma line Nb2 (65 kDa) ( Fig.…”

Long and short forms of the ovine prolactin receptor: cDNA cloning and genomic analysis reveal that the two forms arise by different alternative splicing mechanisms in ruminants and in rodents

“…Recently, however, a partial cDNA sequence was isolated (Anthony et al 1995) that suggested the existence of s-PR in the ovine. Therefore, in order to gain insight into this interesting possibility, we undertook the cloning of full-length long ovine PR (l-oPR) and s-oPR cDNAs.…”