Reichenstein, M., Institute of Animal Science, ARO, Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel
German, T., Institute of Animal Science, ARO, Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel
Barash, I., Institute of Animal Science, ARO, Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel

β-Lactoglobulin (BLG) is a major ruminant milk protein. A regulatory element, termed BLG-e1, was defined in the distal region of the ovine BLG gene promoter. This 299-bp element lacks the established cis-regulatory sequences that affect milk-protein gene expression. Nevertheless, it alters the binding of downstream BLG sequences to histone H4 and the sensitivity of the histone-DNA complexes to trichostatin A treatment. In mammary cells cultured under favorable lactogenic conditions, BLG-e1 acts as a potent, position-independent silencer of BLG/luciferase expression, and similarly affects the promoter activity of the mouse whey acidic protein gene. Intragenic sequences upstream of BLG exon 2 reverse the silencing effect of BLG-e1 in vitro and in transgenic mice. © 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.