Restriction landmark genomic scanning of mouse liver tumors for gene amplification: overexpression of cyclin A2.
SV40 T/t antigen-induced liver tumors from transgenic mice were analyzed by Restriction Landmark Genomic Scanning (RLGS). Using NotI as the restriction landmark, RLGS targets CpG islands found in gene-rich regions of the genome. Since many RLGS landmarks are mapped, the candidate gene approach can be used to help determine which genes are altered in tumors. RLGS analysis revealed one tumor-specific amplification mapping close to CcnA2 (cyclin A2) and Fgf2 (fibroblast growth factor 2). Southern analysis confirmed that both oncogenes are amplified in this tumor and in a second, independent liver tumor. Whereas Fgf2 RNA is undetectable in tumors, CcnA2 RNA and cyclin A2 protein was overexpressed in 25 and 50% of tumors, respectively. Combining RLGS with the candidate gene approach indicates that cyclin A2 amplification and overexpression is a likely selected event in transgenic mouse liver tumors. Our results also indicate that our mouse model for liver tumorigenesis in mice accurately recapitulates events observed in human hepatocellular carcinoma.
Haddad
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Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
Morrow
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D000367:Age Factors; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002874:Chromosome Mapping; D018899:CpG Islands; D019925:Cyclin A / Q000096:biosynthesis* / Q000235:genetics*; D056751:Cyclin A2; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis / Q000235:genetics; D005819:Genetic Markers; D008114:Liver Neoplasms, Experimental / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008957:Models, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase / Q000235:genetics; D015854:Up-Regulation
C503721:CCNA2 protein, human; D019925:Cyclin A; D056751:Cyclin A2; D005819:Genetic Markers; D016222:Fibroblast Growth Factor 2; D015252:Deoxyribonucleases, Type II Site-Specific; C038565:GCGGCCGC-specific type II deoxyribonucleases