Brain-specific enhancement of the mouse neurofilament heavy gene promoter in vitro.

We have investigated the DNA elements responsible for transcription from the proximal portion of the mouse neurofilament heavy gene (NF-H) promoter by in vitro transcription using extracts from expressing (brain) and non-expressing (liver) tissues. We have found that constructs containing 5' region from -1314 to -115 exhibit a 3-5-fold higher level of NF-H promoter activity, relative to the adenovirus major late promoter (pML), in brain versus liver extracts. Deletion to -85 lowers the level of brain transcription by 2-fold, while deletion from -65 through -31 reduces transcription by 5-fold to a relatively strong (10% of pML) basal level. Basal level expression is observed in all deletions transcribed with liver extract. Deletion to -24 (TATA-less) abolishes promoter activity with both extracts. Deletion of the -115 to -65 region from a larger construct reduces transcription in brain extracts to basal levels, suggesting that this region contains the elements necessary for the brain-specific enhancement of promoter function. Mutation of a palindromic sequence within this region abolishes brain-specific enhanced promoter activity. This loss of enhanced transcriptional activity is correlated with the loss of a shifted band in gel shift assays. Our studies suggest that the sequence (-106)GGGGAGGAGG-(15 bp)-CCTCCTCCCC(-72) (where bp = base pairs) is important in brain-specific enhancement of transcription from the mouse NF-H promoter.