Heterogeneous mutations in the gene encoding the [alpha]-subunit of the stimulatory G protein of adenylyl cyclase in Albright hereditary osteodystrophy
- Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)
To identify mutations that lead to G[sub 8][alpha] deficiency, the authors isolated genomic DNA from patients with AHO and used the polymerase chain reaction to amplify exons of the G[sub 8][alpha] genes. DNA was amplified using intron-specific oligonucleotide primers flanking exons of the G[sub 8][alpha] gene. To optimize the ability to detect mutations, one oligonucleotide from each primer pair was synthesized with a 5' GC-clamp. Amplified G[sub 8][alpha] gene fragments were analyzed by denaturing gradient gel electrophoresis in order to detect mutations that alter the melting point of the double-stranded DNA fragment. Using this technique, the authors have identified and characterized three mutations and one neutral polymorphism. The polymorphism, located in exon 5, consisted of a T [yields] C substitution that conserves the isoleucine residue at codon 131 (ATT [yields] ATC). Two mutations were missense mutations, which in one family consisted of a nucleotide substitution (T [yields] C) in exon 4 that results in replacement of Leu by Pro at codon 99 of the G[sub 8][alpha] molecule. Affected subjects in a second family had a single base (C [yields] T) mutation in exon 6 that resulted in replacement of Arg by Cys at codon 165. A 4-base pair deletion (GTGG) in exon 8 at position +214 was identified in one G[sub 8][alpha] allele from each affected subject in the third family. This mutation causes a frameshift after the codon for Gln[sup 213] that results in a premature stop codon 81 base pair after that deletion. Immunoblot analysis of plasma membranes prepared from cultured fibroblasts or erythrocytes indicated that levels of immunoactive G[sub 8][alpha] protein were decreased in all affected subjects. It is concluded that heterogeneous mutations in the gene encoding G[sub 8][alpha], including deletions and single amino acid substitutions, are responsible for G[sub 8][alpha] deficiency in AHO. 44 refs., 9 figs., 1 tab.
- OSTI ID:
- 6441282
- Journal Information:
- Journal of Clinical Endocrinology and Metabolism; (United States), Vol. 76:6; ISSN 0021-972X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Characterization of a de novo 43-bp deletion of the Gs[alpha] gene (GNAS1) in Albright hereditary osteodystrophy
Mutational analysis of Btk, the defective gene in X-linked agammaglobulinemia
Related Subjects
BONE TISSUES
HEREDITARY DISEASES
MEMBRANE PROTEINS
GENE MUTATIONS
CYCLASES
DNA SEQUENCING
GUANINE
NUCLEOTIDES
RFLPS
AMINES
ANIMAL TISSUES
AROMATICS
AZAARENES
BODY
CONNECTIVE TISSUE
DISEASES
ENZYMES
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
LYASES
MUTATIONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PURINES
STRUCTURAL CHEMICAL ANALYSIS
TISSUES
550400* - Genetics