Modulation of the promoter region of prepro-hypocretin by alpha-interferon

Hypocretins 1 and 2 (also called orexins A and B, respectively) are hypotha lamic neuropeptides that have recently been shown to be involved in the sle ep disorder narcolepsy and possibly in the normal regulation of sleep and w ake functions. These two peptides are derived from a single precursor molec ule called prepro-hypocretin, also known as prepro-orexin. We have cloned a 450 bp fragment from the 5'-flanking region of the human prepro-hypocretin gene and demonstrated that this fragment has promoter activity in vitro. D eletions at the 5' end from -450 to -188 reduced the promoter activity by s imilar to 50%. Further deletion from the 5'-end to -69 almost completely ab olished promoter activity. The 450 bp fragment contains a number of potenti al transcription factor binding sites, including an interferon (IFN) respon se element. Our studies: demonstrate that alpha -IFN strongly inhibits the promoter activity of both 450 and 188 bp fragments in a dose-dependent mann er. The inhibitory effect of alpha -IFN is consistent with recent studies w hich suggest that hypocretin 1/orexin A may be involved in modulating arous al states and with the literature indicating involvement of immune-related molecules in sleep regulation. (C) 2001 Elsevier Science B.V. All rights re served.