The bovine α-lactalbumin promoter directs expression of ovine trophoblast interferon in the mammary gland of transgenic mice

A hybrid construct derived from ovine trophoblastin cDNA and bovine α-lactalbumin-encoding gene, was injected into the pronuclei of mouse eggs. In one of the resulting transgenic mouse lines, expression of the hybrid construct was detected and found to be limited to the mammary gland of lactating females which secreted active ovine trophoblastin. This strongly suggests that important cis-acting DNA sequences involved in tissue-specific expression of the bovine gene are located within the second half of the 3′ untranslated region, or/and the proximal 5′and 3′ regions flanking the transcriptional unit.