Transcriptional state and chromatin structure of the murine entactin and laminin gamma 1 genes

The positions of nucleosomes in the proximal 5' regions of the coordinately regulated murine entactin/nidogen and laminin gamma1 genes have been ident ified in four different transcriptional states - constitutively off, basal, induced, and constitutively induced. In the entactin gene a 450 base pair (bp) region of open chromatin is present between three positioned nucleosom es and the transcriptional start site in the basal, induced, and constituti vely induced states. Additionally there is a 200 bp open chromatin region a t similar to -2.1 kbp that is only present in the induced and constitutivel y induced states. In the laminin gamma1 gene, a 650 bp region of nucleosome -free chromatin is present between nucleosomes positioned at similar to -75 0 and +120 in all transcriptionally active states. These results suggest th at basal coexpression of these genes requires sites present in these near u pstream regions. The induction to high levels appears to involve additional sites and possibly the production of new and/or the modification of existi ng trans-acting factors. J. Cell. Biochem. 82: 225-233, 2001. (C) 2001 Wile y-Liss, Inc.