Transgenic construct used to analyze potential regulatory elements involved in imprinting in mouse. Contains a UAS-driven lacZ reporter and a w[+] minigene (transcription of both these genes is in the same orientation). A 3.4kb A6-A4 containing region upstream of Mmus\H19 gene, carrying sequences known to be important for imprinting, has been inserted upstream of the UAS-lacZ reporter and the effects on lacZ and w expression have been analyzed.