Genetic analysis of tumorigenesis: XXXII. Localization of constitutionally amplified KRAS sequences to Chinese hamster chromosomes X and Y by in situ hybridization.
The KRAS gene is constitutionally amplified in the Chinese hamster. We have mapped the amplified sequences by in situ hybridization to two major sites on the X and Y chromosomes, Xq4 and Yp2. No autosomal site was detected despite a search under relaxed hybridization conditions. KRAS DNA is amplified about 50-fold compared to a human cell line known to have a diploid number of KRAS sequences, whereas mRNA expression is 5- to 10-fold lower than in normal human cells. While mRNA expression levels do not necessarily parallel gene copy number, the low expression level strongly suggests that the amplified sequences are transcriptionally silent. It is suggested that the amplified sequences arose from the original KRAS gene on chromosome 8 and that the KRAS sequences on the Y chromosome arose by X-Y recombination.
Stenman
G
G
Division of Cancer Genetics, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Anisowicz
A
A
Sager
R
R
D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002874:Chromosome Mapping; D006224:Cricetinae / Q000235:genetics*; D003412:Cricetulus / Q000235:genetics*; D005784:Gene Amplification; D005786:Gene Expression Regulation; D009693:Nucleic Acid Hybridization; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D014960:X Chromosome; D014998:Y Chromosome
D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras)