The effect of regulatory sequences of αS1-casein gene on the expression of the lacZ-gene in loach Misgurnus fossilis L. transgenic embryos

Transient expression of recombinant plasmids carrying the lacZ gene under the control of either bovine alpha S1-casein gene tissue-specific promoter-enhancer region or highly homologous goat alpha S1-casein gene promoter-enhancer region with supplementary regulatory sequences of the goat gene were studied in Misgurnus fossilis L. loach embryos. It has been shown previously that the expression of the constructs carrying these regulatory elements in transgenic mice occurred primarily in the mammary glands. At early developmental stages, loach embryos and early prelarvae showed nonspecific and mosaic transient expression of lacZ carrying casein regulatory sequences. Transgenic activity was the highest in 1-3-day embryos. At the same time, the efficiency of expression of lacZ gene carrying regulatory sequences of the alpha S1-casein gene of goat was higher than with the promoter - enhancer region of the bovine alpha S1-casein gene. Thus, regulatory sequences of the bovine or goat alpha S1-casein gene appeared capable of providing similar transient expression of reporter gene in the loach embryos. This model can be used for rapid testing of promoter-enhancer activity of transgenes.