Advertisement
Research Article Free access | 10.1172/JCI114393
Division of Hematology Oncology, Children's Hospital Boston, Massachusetts 02115.
Find articles by Dinauer, M. in: JCI | PubMed | Google Scholar
Division of Hematology Oncology, Children's Hospital Boston, Massachusetts 02115.
Find articles by Curnutte, J. in: JCI | PubMed | Google Scholar
Division of Hematology Oncology, Children's Hospital Boston, Massachusetts 02115.
Find articles by Rosen, H. in: JCI | PubMed | Google Scholar
Division of Hematology Oncology, Children's Hospital Boston, Massachusetts 02115.
Find articles by Orkin, S. in: JCI | PubMed | Google Scholar
Published December 1, 1989 - More info
A membrane-bound cytochrome b, a heterodimer formed by a 91-kD glycoprotein and a 22-kD polypeptide, is a critical component of the phagocyte NADPH-oxidase responsible for the generation of superoxide anion. Mutations in the gene for the 91-kD chain of this cytochrome result in the X-linked form of chronic granulomatous disease (CGD), in which phagocytes are unable to produce superoxide. Typically, there is a marked deficiency of the 91-kD subunit and the cytochrome spectrum is absent (X- CGD). In a variant form of CGD with X-linked inheritance, affected males have a normal visible absorbance spectrum of cytochrome b, yet fail to generate superoxide (X+ CGD). The size and abundance of the mRNA for the 91-kD subunit and its encoded protein were examined and appeared normal. To search for a putative mutation in the coding sequence of the 91-kD subunit gene, the corresponding RNA from an affected X+ male was amplified by the polymerase chain reaction and sequenced. A single nucleotide change, a C----A transversion, was identified that predicts a nonconservative Pro----His substitution at residue 415 of the encoded protein. Hybridization of amplified genomic DNA with allele-specific oligonucleotide probes demonstrated the mutation to be specific to affected X+ males and the carrier state. These results strengthen the concept that all X-linked CGD relates to mutations affecting the expression or structure of the 91-kD cytochrome b subunit. The mechanism by which the Pro 415----His mutation renders the oxidase nonfunctional is unknown, but may involve an impaired interaction with other components of the oxidase.
Images.