ABSTRACT
The neurofibromatosis 1 (NF1) gene product, neurofibromin, is a tumor suppressor gene product capable of inhibiting the growth of cells in culture. If neurofibromin suppresses cell growth by arresting cells in G0 or G1, its expression might be regulated in a cell cycle-dependent fashion. In this study, we demonstrate that RAT-1A fibroblasts arrested in G0/G1 by serum starvation and then released to progress through the cell cycle do not demonstrate significant changes in NF1 expression. However, when arrested in G0/G1 by contact inhibition, NF1 expression in these cells is reversibly upregulated within 72 h, suggesting that NF1 expression is a late event associated with cell growth arrest which may contribute to the maintenance of the differentiated state.
Subject(s)
Gene Expression/physiology , Genes, Neurofibromatosis 1/physiology , Animals , Cell Cycle/physiology , Cell Division/physiology , Cells, Cultured , Fibroblasts/physiology , Neurofibromin 1 , Polymerase Chain Reaction , Protein Biosynthesis , RNA/biosynthesis , RatsABSTRACT
Oculodentodigital dysplasia (ODDD) is an autosomal dominant disorder involving eye and face abnormalities, syndactyly, and enamel hypoplasia. Some individuals with ODDD also have spastic paraparesis. Previously, we reported on a woman with sporadic ODDD and progressive neurologic dysfunction who had cerebral white matter abnormalities demonstrated by magnetic resonance imaging (MRI). We now describe a 2-generation family with ODDD and progressive paraparesis associated with leukodystrophic changes documented by MRI. This family represents one of the largest pedigrees with ODDD described so far. The presence of abnormal white matter changes in both sporadic and inherited forms of ODDD suggests that the phenotype of ODDD should be expanded to include spastic paraparesis.
Subject(s)
Abnormalities, Multiple , Eye Abnormalities , Syndactyly/complications , Tooth Abnormalities , Abnormalities, Multiple/genetics , Adolescent , Adult , Canavan Disease/complications , Canavan Disease/diagnostic imaging , Canavan Disease/genetics , Child , Child, Preschool , Eye Abnormalities/genetics , Face/abnormalities , Female , Humans , Magnetic Resonance Imaging , Male , Paraparesis, Tropical Spastic/complications , Pedigree , Radiography , Tooth Abnormalities/geneticsABSTRACT
Vascular pathology is an underestimated complication of neurofibromatosis 1 (NF1). Manifestations include renovascular stenosis with associated hypertension, cerebrovascular occlusion, visceral ischaemia and aneurysms of smaller arteries. This is illustrated by a woman recently evaluated in our Neurofibromatosis Program who had multiple cerebrovascular and renovascular abnormalities. To determine the contribution of NF1 expression to NF1 vasculopathy, the expression of the NF1 gene product, neurofibromin, was examined in blood vessels. Neurofibromin was detected in the endothelial cell layer of rat cerebral vessels, renal arteries, and aorta by immunohistochemistry. Cultured bovine cerebral endothelial cells were found to express NF1 mRNA by RT-PCR and neurofibromin by Western immunoblotting and immunocytochemistry. Neurofibromin expression was also detected in the smooth muscle layer of the aorta but not of cerebral or renal vessels. The vascular abnormalities of NF1 are reviewed and possible pathogenesis with respect to neurofibromin expression is discussed.
