title: Identification of a second-site suppressor mutation of the GTPase defect associated with McCune-Albright syndrome: a model using the yeast heterotrimeric G protein, GPA1.
abstract: McCune-Albright syndrome (MAS) causes a variety of bone and endocrine abnormalities due to the post-zygotic mutation of the alpha subunit of the stimulatory G-protein Gsalpha. This mutation causes signal-independent activity of the G-protein in the affected cells. We report the development of a system to study the effects of MAS mutations using Saccharomyces cerevisiae, wherein activation of the yeast G-protein pathway results in growth arrest in a genetically recessive fashion. We introduced the MAS mutation into the analogous site in the yeast Galpha gene, GPA1 and randomly mutated the gene to produce intragenic suppressors. Yeast with normal and mutated G-protein genes were induced to lose the normal gene, and mutations able to intragenically suppress the constitutive activity of the MAS mutation were identified based on their ability to form colonies. We report one mutation in GPA1, also in the active site, that is an intragenic suppressor of the MAS defect.
authors.affiliation: Trinity Christian College, Biology Department, Palos Heights, IL 60463, USA.
authors.forename: Laura S
authors.initials: LS
authors.lastname: Ooms
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Koster
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Mitchell
authors.forename: Robin
authors.initials: R
authors.lastname: Pals-Rylaarsdam
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D005359:Fibrous Dysplasia, Polyostotic / Q000235:genetics / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000737:chemistry / Q000235:genetics*; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics*; D015398:Signal Transduction; D013489:Suppression, Genetic
chemical_list: D044385:GTP-Binding Protein alpha Subunits; D029701:Saccharomyces cerevisiae Proteins; C084293:GPA1 protein, S cerevisiae; D043802:GTP-Binding Protein alpha Subunits, Gq-G11