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Gene expression in the mammary gland
S Harris1, M McClenaghan, J P Simons
1AFRC Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin, Midlothian, UK.
Journal of Reproduction and Fertility
|March 1, 1990
Summary
Transgenic mice successfully produced beta-lactoglobulin (BLG) protein in milk using an ovine genomic clone. This demonstrates that sheep BLG gene regulatory sequences function correctly in mice for mammary gland expression.
Area of Science:
- Genetics
- Molecular Biology
- Biotechnology
Background:
- The ovine beta-lactoglobulin (BLG) gene is a key milk protein in sheep.
- Understanding the regulatory elements of BLG is crucial for genetic engineering in livestock.
Purpose of the Study:
- To assess the functionality of ovine BLG gene regulatory sequences in a heterologous host, specifically transgenic mice.
- To establish a model for studying mammary gland-specific gene expression and producing foreign proteins in milk.
Main Methods:
- Generation of transgenic mice carrying an ovine BLG genomic clone (SS1).
- Analysis of BLG protein production and gene expression in the mammary glands of transgenic mice.
- Characterization of the minimal DNA construct required for directing BLG to mouse milk.
Main Results:
- Transgenic mice produced significant quantities of BLG protein in their milk.
- The smallest functional BLG construct included approximately 7.3 kb of genomic DNA, with a 0.8 kb promoter region.
- Gene expression was tissue-specific and regulated similarly to sheep, indicating conserved regulatory mechanisms.
Conclusions:
- Ovine BLG gene cis-acting sequences are correctly interpreted in mice, validating their use for studying ruminant mammary expression.
- Transgenic mice serve as a valuable model for evaluating gene constructs for foreign protein production in milk.
- Further studies on BLG promoter sequences and DNA-protein interactions will enhance understanding of milk protein gene regulation.