Abstract
Parkinson's disease (PD) is a dopaminergic neurodegeneration disease, which causes movement disorders. We assessed the role of two candidate genes encoding enzymes involved in dopaminergic transmission. Dopamine transporter (DAT) is a membrane protein responsible for reuptake of dopamine into presynaptic terminals. Dopamine □-hydroxylase (DBH) is the enzyme which catalyses the conversion of dopamine into norepinephrine, the third step of catecholamine biosynthesis. A 40-nucleotide repeats polymorphism in the 3'-untranslated region of DAT, and a TaqI RFLP (restriction fragment length polymorphism) and a DNRP (dinucleotide repeat polymorphism) of DBH were used to determine allelic and genotypic distributionS in PD and control. Our statistic analyses showed that neither DAT nor DBH is significantly associated with Parkinson's disease in our sample population from Taiwan. Monoamine oxidase B (MAO-B) is one of two types of MAO isoenzymes which are important for metabolic degradation of biogenic amines. MAOB has been implicated in genetic predisposition for PD. Two sequence variation sites were found in the promoter regions of MAOB among five individuals. One of the variation sites resides on a BscGI restriction enzyme recognition site and hence constitutes a new RFLP marker for MAOB. The fact that this variation site is one base upstream from a putative AP-1 binding site suggests that it may affect MAOB expression. RT-PCR (reverse transcription-PCR) was established to measure the mRNA levels of MAOB and DBH in HeLa cell line and IMR-32 neuroblastoma cell line. □-actin mRNA was used as an internal control. Our calibration studies demonstrated that the system could be used for detecting variations in mRNA levels. MAOB and DBH in a range from 0.1 ng to 4 ng of total RNA and MAOA in a range from 50 ng to 100 ng of total RNA. This sensitive and efficient system should be useful for studying the effects of exogenic factors on mRNA levels of DBH and MAO in different cell cultures.