HNMP-1 - A NOVEL HEMATOPOIETIC AND NEURAL MEMBRANE-PROTEIN DIFFERENTIALLY REGULATED IN NEURAL DEVELOPMENT AND INJURY

The hnmp-1 (hematopoietic neural membrane protein) gene encodes a prot ein with striking similarity to the tetra-transmembrane-spanning prote in encoded by pmp22. hnmp-1 was cloned from an elutriated human monocy te library and is expressed in various human hematopoietic and lymphoi d lineages as well as adult mouse spleen and thymus. In the mouse nerv ous system, HNMP-1 mRNA is temporally expressed by Schwann cells durin g sciatic nerve myelination. Dorsal root ganglia sensory and spinal co rd alpha-motoneurons acquire HNMP-1 protein selectively throughout dev elopment. In the fiber tracts of the spinal card and in sciatic nerve, HNMP-1 protein is axon-associated, Additionally a rapid and sustained level of HNMP-1 expression is observed in response to acute PNS injur y. HNMP-1 is constituitively induced in sciatic nerve of Trembler J mi ce, which are mutant for pmp22 and have a demyelinating/hypomyelinatin g phenotype. The expression pattern of HNMP-1 suggests a possible role for this molecule during active myelination.