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Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos
Published on: June 6, 2016
Expression of the mouse homologue for the human GCDFP-15/PIP gene during pre- and early post-natal development
Beverley Lee1, Geetanjalee Modha, Peter H Watson
1Department of Pathology, Faculty of Medicine, University of Manitoba, 770 Bannatyne Avenue, Man., R3E 0W3 Winnipeg, Canada.
Insights
The mouse submaxillary gland/prolactin inducible protein (mSMGP/mPIP) is expressed early in salivary gland development. Its presence in saliva suggests a potential protective role in mice.
Area of Science:
- Developmental Biology
- Molecular Biology
- Biochemistry
Background:
- The function of mouse submaxillary gland/prolactin inducible protein (mSMGP/mPIP), a homolog of human GCDFP-15/hPIP, is unknown.
- The human counterpart is found in apocrine glands and aberrantly expressed in breast and prostate cancers.
- Previous studies showed tissue-specific and hormonal regulation of mSMGP/mPIP in adult mice and rats.
Purpose of the Study:
- To investigate the endogenous gene expression pattern of mSMGP/mPIP during mouse embryonic and early postnatal development.
- To determine the spatial and temporal distribution of mSMGP/mPIP during gland development.
Main Methods:
- Gene expression analysis using RT-PCR and Southern blot.
- In situ hybridization for transcript localization.
- Examination of expression during embryonic (E14, E18) and postnatal stages.
Main Results:
- mSMGP/mPIP gene expression was detected as early as embryonic day 14 (E14) in the developing submandibular gland.
- Transcripts were localized in proacinar cells at E18 and expression was maintained postnatally.
- Expression was also found in sublingual, parotid, lacrimal glands, reproductive tissues, and prostate (turned off by 10 weeks).
Conclusions:
- The early expression suggests a functional role for mSMGP/mPIP in developing salivary glands.
- The spatial and temporal expression pattern, along with its presence in saliva and bacterial binding capacity, indicates a potential protective role for mSMGP/mPIP in mice.
Abstract:
The function of the mouse submaxillary gland/prolactin inducible protein (mSMGP/mPIP), the homologue of the human gross cystic disease fluid protein 15 (GCDFP-15)/prolactin inducible protein (hPIP) remains unknown. The human gene, normally expressed in apocrine glands of healthy individuals, is aberrantly expressed in human breast cancers where it is regulated by hormones including androgens, and in prostate cancers. We have previously reported that in the adult mouse and rat, gene expression is tissue-specific for the salivary and lacrimal glands, and is hormonally regulated. In this study, we examine the endogenous pattern of mouse SMGP/PIP (mSMGP/mPIP) gene expression in mid- and late-embryonic, and in early postnatal development. Gene expression was analyzed by RT-PCR followed by Southern blot analysis, and by in situ hybridization. Gene expression was detected in the submandibular gland as early as embryonic day 14 (E14), a period that coincides with the initiation of submandibular gland development in the embryo, suggesting that mSMGP/mPIP may have a functional role in the developing gland. Nearing the end of gestation, E18, mSMGP/mPIP transcripts were localized in the proacinar cells of the gland, and gene expression continued to be maintained following birth. In addition, during early postnatal development, mSMGP/mPIP gene expression was detected in the other two major salivary glands, the sublingual and parotid, as well as in the lacrimal gland and in reproductive tissues. In the prostate, gene expression was turned off by 10 weeks of age. The spatial and temporal pattern of the mSMGP/mPIP gene expression, in addition to our recent demonstration that mSMGP/mPIP is found in mouse saliva and can bind bacteria, suggest that this protein may have a protective role in the mouse.
