Expression of a heterologous protein C in mammary tissue of transgenic animals using a long whey acidic protein promoter

An isolated DNA sequence which regulates the expression of a heterologous gene composed of a mouse whey acidic protein promoter having a length of greater than about 2.4 kb extending upstream from the unique KpnI site in the mouse whey acidic protein gene is disclosed. Specifically a mouse whey acidic protein promoter of about 4.1-4.2 kb in length extending upstream from the unique KpnI site is preferred. This mouse whey acid protein promoter is operably linked to a DNA sequence encoding a heterologous polypeptide and used to prepare transgenic non-human mammals expressing the heterologous polypeptide in their milk. Particularly efficient expression of both cDNAs and genomic DNAs encoding heterologous polypeptides was obtained in transgenic non-human mammals using this promoter, known as the long whey acidic protein promoter.