Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, we have analyzed the developmental expression of the prolactin receptor (PRL-R) gene in the ewe mammary gland during pregnancy and lactation. Using Northern and slot-blot analysis and in situ hybridization, we showed that the level of PRL-R mRNA in mammary epithelial cells increased during the second half of pregnancy, decreased at the end of pregnancy, and remained relatively stable during lactation with a level above that observed at the beginning of pregnancy. As shown by RNase protection assay, the ratio of the long to the short form of the PRL-R mRNA was always above 1. This ratio increased between Day 70 of pregnancy and term and decreased progressively during lactation. The high level of PRL-R mRNA before the induction of alphaS1-casein gene expression suggests that PRL may be involved in the growth and development of the mammary gland. More precisely, the increase of the ratio of the long to the short form of the PRL-R during lactogenesis suggests that the latter form may have a dominant negative action in the activation of milk protein gene transcription. Thus the long/short-form ratio of the PRL-R may play a key role in the shift between growth and differentiation of the mammary gland.
 ...
PMID:Developmental expression and localization of the prolactin receptor (PRL-R) gene in ewe mammary gland during pregnancy and lactation: estimation of the ratio of the two forms of PRL-R messenger ribonucleic acid. 960 66

In order to examine the hormonal regulation of the prolactin-receptor (PRL-R) gene expression during mammary gland development, ewes were treated to induce lactation via an estrogen-progesterone-hydrocortisone and ovine growth hormone treatment. In situ hybridization analysis was used and revealed that sex steroids increased PRL-R mRNA levels in the mammary gland. Using RNase protection assay we showed that the estradiol + progesterone treatment increased both the levels of the long and the short forms of PRL-R mRNA. Addition of hydrocortisone increased the level of alphaS1-casein transcripts and the level of the ratio of the long to the short form of the PRL-R mRNA. This ratio can be further enhanced by addition of ovine growth hormone to the latter treatment. This suggests a role of hydrocortisone and ovine growth hormone in the alternative splicing that leads to the preferential expression of the long form of the PRL-R mRNA. In conclusion, the present experiments suggest that estrogen, progesterone and hydrocortisone are the major regulators of the PRL-R gene expression during pregnancy and prepare the mammary gland for its differentiation.
 ...
PMID:Increase in prolactin receptor (PRL-R) mRNA level in the mammary gland after hormonal induction of lactation in virgin ewes. 1070 63