CDNA cloning, mapping and expression of the mouse Propionyl CoA Carboxylase Beta ( pccb), the gene for human type II propionic acidaemia

Abstract

Propionyl CoA carboxylase (PCC) is a mitochondrial, biotin-dependent enzyme involved in the catabolism of amino acids, odd-chained fatty acids and other metabolites. PCC is composed of two equal subunits, α and β, which are encoded by two separate genes at two distinct human loci. Mutations of either gene in humans results in propionic acidemia (PA). To identify the mouse cDNA for the propionyl CoA carboxylase β-subunit (pccb), we have screened the mouse EST database using the human sequence. The murine mRNA transcript is ~2.3 kb, nearly 500 bps larger than the human ~1.8 kb transcript. A PAC genomic DNA clone from the mouse was also isolated and used to generate probes and PCR primers for mapping the pccb locus in the mouse. Both the C57Bl/6JEi and Spret/Ei alleles for regions flanking the pccb gene were sequenced to identify RFLPs. The Jackson Laboratory BSS and BSB backcross panel DNAs were then analyzed using a DdeI polymorphism placing the pccb locus on mouse chromosome 9. Northern blots of adult tissue show that the pccb gene is broadly expressed in the mouse. The ~2.3 kb transcript is most abundantly expressed in the kidney, liver, small intestine and stomach tissues.