Hormonal influences on beta-lactoglobulin transgene expression inferred from chromatin structure.
The major milk whey protein of ruminants is beta-lactoglobulin. Transgenic mice which carry genomic fragments of ovine beta-lactoglobulin express the transgene at high levels in the mammary gland. Using DNaseI as a probe for transcription complex formation in chromatin, the temporal induction pattern of beta-lactoglobulin in transgenic mice has been addressed and compared to the known hormonal profiles during pregnancy. Prior to the 9th day of pregnancy no obvious hypersensitivity to DNaseI digestion at the beta-lactoglobulin promoter was evident. From the 9th day of pregnancy through to lactation, the beta-lactoglobulin promoter displays DNaseI hypersensitivity. These results support the hypothesis that placental lactogens are the major lactogenic influence from mid-pregnancy to parturition.
Whitelaw
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CB
Division of Molecular Biology, Roslin Institute, Edinburgh, Scotland, United Kingdom. bruce.whitelaw@bbsrc.ac.uk
D000818:Animals; D002843:Chromatin / Q000737:chemistry / Q000502:physiology*; D003850:Deoxyribonuclease I; D005260:Female; D007774:Lactation / Q000378:metabolism; D007782:Lactoglobulins / Q000096:biosynthesis* / Q000235:genetics*; D008321:Mammary Glands, Animal / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D010928:Placental Lactogen / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012756:Sheep; D014158:Transcription, Genetic / Q000502:physiology*
D002843:Chromatin; D007782:Lactoglobulins; D010928:Placental Lactogen; D003850:Deoxyribonuclease I