CHARACTERIZATION OF THE MOUSE NEUROFILAMENT LIGHT (NF-L) GENE PROMOTER BY IN-VITRO TRANSCRIPTION

We have used in vitro transcription to access the basic sequences and factors required for the transcription of the mouse neurofilament ligh t promoter (pNF-L) in the absence of chromatin structure. Deletion fro m -1.7 to -154 results in little change in NF-L promoter activity usin g nuclear extracts from either brain (expressing) or liver (non-expres sing) tissues. Further deletion to -29 results in a gradual five-fold drop in promoter activity in both extracts. Only replacement of the en tire -148 to -29 region results in a drop in NF-L promoter activity to basal levels. Thus, the NF-L promoter differs from the mouse NF heavy (NF-H) and mid-sized (NF-M) promoters in that no specific sequence wi thin the immediate upstream NF-L promoter region (-154 to -29) appears to be responsible for enhancement or brain-specific transcription. We show that the order of strength of the three NF promoters is NF-H > N F-M > NF-L and identify sequences that can increase or reduce transcri ption when placed in front of heterologous NF promoters. We conclude t hat the NF-L promoter is a modular, weak and promiscuous promoter whos e regulation differs from NF-H or NF-M. Our data suggest that chromati n structure may play an important role in the regulation of the NF-L p romoter. (C) 1998 Elsevier Science B.V. All rights reserved.