POSITIVE ELEMENTS IN THE LAMININ GAMMA-1 GENE SYNERGIZE TO ACTIVATE HIGH-LEVEL TRANSCRIPTION DURING CELLULAR-DIFFERENTIATION

Transcription of the murine laminin gamma 1 gene is activated during r etinoic acid/cAMP induced differentiation of F9 embryonal carcinoma ce lls, Positive transcription control elements associated with two DNase I hypersensitive regions in the large first intron of the gene have b een identified which confer a differentiation response on the laminin gamma 1 promoter, However, the kinetics of transcriptional activation suggest each DNA region interacts with transcription factors appearing at different times during differentiation, Synergy between the two re gions in cis causes high level activation.