CDNA sequencing of branched chain 2-oxo acid dehydrogenase complex (BCOADC)-E2 in Japanese patients with primary biliary cirrhosis

Abstract

Complimentary DNA (cDNA) of branched chain 2-oxo acid dehydrogenase complex (BCOADC)-E2, which is frequently reacted with anti-mitochondrial antibody in primary biliary cirrhosis (PBC), has been cloned and identified in Europe. There have been no reports regarding cDNA sequence of BCOADC-E2 in Japanese PBC patients. It has also not been determined whether the cDNA sequence of BCOADC-E2 of patients with PBC is the same as or different from that of healthy individuals. The purposes of this study were to investigate the mutation of BCOADC-E2 cDNA and the difference of the cDNA sequence between Japanese PBC patients and healthy controls. Total RNA was extracted from peripheral lymphocyte samples, and the cDNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR). Using the amplified cDNA as a template, BCOADC-E2 cDNA including the lipoic acid binding domain which constitutes the major epitope in BCOADC-E2 was amplified by PCR. The direct sequencing of these PCR products was performed. The cDNA sequence of BCOADC-E2 of the seven Japanese PBC patients was found to be the same as that of European patients reported earlier, and not different from that of the three Japanese normal controls. These data indicate that the antibody production of BCOADC-E2 in PBC patients is not associated with the disease-specific gene mutations of BCOADC-E2 cDNA.