Genomic structure of the PIK3CG gene on chromosome band 7q22 and evaluation as a candidate myeloid tumor suppressor.
PIK3CG, which encodes the catalytic subunit p110 gamma of phosphoinositide 3-OH-kinase-gamma (PI3K gamma), has been assigned to chromosome band 7q22, a region that is frequently deleted in myeloid malignancies. PI3K gamma-mutant mice have hematologic defects and are predisposed to colon cancer. On the basis of these data, PIK3CG was evaluated as a candidate myeloid tumor suppressor gene (TSG). PIK3CG was mapped by fluorescence in situ hybridization adjacent and telomeric to a commonly deleted segment defined previously in myeloid leukemias with breakpoints within 7q22. PIK3CG contains 10 exons and spans approximately 37 kilobases of genomic DNA. Forty leukemias with monosomy 7 or a del(7q) were screened for PIK3CG mutations. Two patients had missense variations affecting residue 859 in the N-terminal catalytic domain of the protein. This allele was also detected in unaffected parents and in 1 of 60 control alleles; it probably represents a polymorphism. PIK3CG is unlikely to act as a recessive TSG in myeloid leukemias with monosomy 7.
Kratz
Christian P
CP
Department of Pediatrics, University of California, San Francisco 94143, USA.
Emerling
Brooke M
BM
Bonifas
Jeannette
J
Wang
Winfred
W
Green
Eric D
ED
Le Beau
Michelle M
MM
Shannon
Kevin M
KM
D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D002897:Chromosomes, Human, Pair 7; D004252:DNA Mutational Analysis; D019992:Databases as Topic; D017353:Gene Deletion; D016147:Genes, Tumor Suppressor; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007951:Leukemia, Myeloid / Q000235:genetics*; D009006:Monosomy; D020125:Mutation, Missense; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
D019869:Phosphatidylinositol 3-Kinases