title: Expression of p67 (Munc-18) in adult human brain and neuroectodermal tumors of human central nervous system.
abstract: p67 (Munc-18), is a neuron-specific protein of 67 kDa, known for its ability to bind with syntaxin and also to copurify with neuronal cdc2-like kinase. Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons. In the present study, we have looked for p67 expression in normal human brain and various neuroectodermal tumors. Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia. Among neuroectodermal tumors, expression of p67 was observed in 100% of the tumors of neuronal origin studied, especially in the mature neuronal cell population of these tumors. Western immunoblot analysis of non-neuronal neuroectodermal tumors failed to reveal the expression of this protein in majority of cases. However, in gliomas and meningiomas, mild cytoplasmic immunohistochemical staining of neoplastic cells was noted in 64.7% and 25% of cases, respectively. Observed mild immunohistochemical staining of these tumors could be due to immunoreactivity to low molecular weight degraded products of p67, as seen on Western blot. The findings suggest that p67, by virtue of its ability to be expressed in postmitotic neurons of adult human brain and in tumors of neuronal origin, may serve as a molecular tool to understand the growth and differentiation of the nervous system in general.
authors.affiliation: Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bangalore, India.
authors.forename: S
authors.initials: S
authors.lastname: Kalidas
authors.forename: V
authors.initials: V
authors.lastname: Santosh
authors.forename: M M
authors.initials: MM
authors.lastname: Shareef
authors.forename: S K
authors.initials: SK
authors.lastname: Shankar
authors.forename: R
authors.initials: R
authors.lastname: Christopher
authors.forename: K T
authors.initials: KT
authors.lastname: Shetty
mesh_terms: D000328:Adult; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000166:cytology* / Q000473:pathology; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000737:chemistry / Q000473:pathology*; D002528:Cerebellar Neoplasms / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008527:Medulloblastoma / Q000473:pathology; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000032:analysis*; D017599:Neuroectodermal Tumors / Q000737:chemistry / Q000473:pathology*; D018242:Neuroectodermal Tumors, Primitive / Q000473:pathology; D051381:Rats; D013116:Spinal Cord / Q000737:chemistry / Q000166:cytology* / Q000473:pathology; D033921:Vesicular Transport Proteins
chemical_list: D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; C497937:STXBP1 protein, human; D033921:Vesicular Transport Proteins