Molecular Biological Studies on the Etiology of Neurodegenerative Diseases.

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Neurodegenerative disorders are characterized by selective loss of particular types of neurons. The identification of genes which are expressed in specific neurons such as motor neurons would bring us better understanding of differentiation of neurons as well as the molecular mechanisms of selectiveloss of the neurons.I have developed a method for isolation of gene which are expressed in particular types of neurons employing subtractive cloning. For the strategy it is crucially important to isolate undegraded RNAs from post-motem brains and spinal cords. First, the stability of messenger RNA in Post-mortem human bains and spinal cords was investigated. It was concluded that messenger RNAs are not degraded as long as 12 hours. Complementary DNA libraries were made from postmortem human brain and spinal cord Analysis of the cDNA libraries have shown the presence of full-length cDNA clones for neuron-specific olase, S100 and myelin-associated glycoprotein.PolyA (+) RNA from human spinal cord was labeled with ^<32>P and reassociated in phenol-emulsion with human brain cDNAs to remove the commonly expressed genes. The human spinal cord cDNA library was screened with the subtracted ^<32>P-labeled probe, and I have succeeded in isolation of four cDNA clones. Northern blot analysis revealed that increased expression of the two cDNA clones. The results suggest a potential feasibility of the strategy for identifying genes expressed in selective neurons.To identify genes involved in the development of juvenile-Parkinsonism, a neuro-degenerative disorder, linkage analysis on tyrosine hydroxylase locus was performed, as previous studies suggested tyrosine hydroxylase is a candidate gene for juvenile Parkinsonism. Linkage analysis employing tyosine hydroxylase gene and adjacent VNTR (variable number of tandem repeat) probes including H-RASI and INS has clearly demonstrated that tyrosine hydroxylase gene is not linked to juvenile Parkinsonism.