EN
Expression of milk protein genes is regulated by hormones, growth factors and extracellular matrix.Prolactin, the major lactogenic hormone, promotes all stages of casein gene expression. Besides prolactin, also growth hormone may directly induce expression of milk protein genes. Computer analysis, mutation experiments and DNA-protein binding experiments enabled indentification of mammary-specific trasnscription factors and cis-regulatory sequences in milk protein gene promoters. Also, transgene technology enables recognition of regulatory sequences in milk protein genes.Moreover, transgenic animals carrying structural genes of human proteins fused to mammary specific promoters are considered as living "bioreactors" designated to produce human proteins for pharmaceutical use.