The cloning of a rat peptidoglycan recognition protein (PGRP) and its induction in brain by sleep deprivation

Peptidoglycan recognition protein (PGRP) binds to peptidoglycan (PG) or liv e bacteria and is upregulated by PG, PGRP is a ubiquitous protein involved in innate immunity. Tag7, a novel cytokine, is also induced by bacterial pr oducts; tag7 is apoptotic to murine L929 cells in a NF-kappaB-independent m anner. Both of these genes are expressed in brain, lymphatic and haematopoi etic tissues. We provide evidence that murine PGRP and tag7 encode identica l transcripts and have structural relationships to lysozymes, Further, we h ave cloned the cDNA of rat PGRP and analyzed its expression in brains of sl eep-deprived and control rats, The mRNA levels of PGRP/tag7 were measured b y RT-PCR and compared to the housekeeping gene porphobilinogen deaminase (P BD), PGRP was constitutively expressed in rat brain. PGRP mRNA was increase d by 43% and 17% in the brainstem and hypothalamus, respectively, in sleep- deprived rats compared to controls, The upregulation of PGRP expression by sleep deprivation suggests a role for PGRP in a homeostatic regulation of s leep. (C) 2001 Academic Press.