The p53 tumor suppressor gene of the marsupial Monodelphis domestica: cloning of exons 4-11 and mutations in exons 5-8 in ultraviolet radiation-induced corneal sarcomas.
Inactivating p53 mutations are found in many ultraviolet radiation (UVR)-induced skin tumors. We examined 12 UVR-induced corneal tumors of the marsupial Monodelphis domestica for mutations in exons 5-8 of p53 and compared their mutational spectrum with that of UVR-induced skin tumors of other species. First we cloned and characterized a cDNA extending from the middle of exon 4 through exon 11 of the Monodelphis p53 gene. Based on the sequence information obtained, primers were designed to amplify introns 4-9 of the gene; intron primers to amplify individually exons 5-8 were subsequently developed. 'Cold' single strand conformational polymorphism analysis followed by reamplification of DNA with altered mobility and cycle sequencing revealed single p53 mutations in four of 12 tumors (33%), including one mutation in exon 5, two identical mutations in exon 7 and one mutation in exon 8. All mutations were at dipyrimidine sites and occurred on the non-transcribed strand. Three of the four were hallmark UVR-induced C-->T alterations. Three of the mutations were found at sites corresponding to human codons 248 and 273, which are mutational hotspots in human and murine UVR-induced squamous cell carcinomas. Our findings suggest that UVR-induced corneal sarcomas in Monodelphis will be valuable in studying mechanisms of p53 mutation in UVR-induced tumors.
Kusewitt
D F
DF
Department of Cell Biology and Physiology, Room 149, Basic Medical Sciences Building, Health Sciences Center, University of New Mexico, Albuquerque, NM 87131, USA.
Sherburn
T E
TE
Miska
K B
KB
Tafoya
G B
GB
Gale
J M
JM
Miller
R D
RD
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003316:Corneal Diseases / Q000235:genetics*; D018076:DNA, Complementary; D005091:Exons; D005134:Eye Neoplasms / Q000235:genetics*; D016158:Genes, p53; D008394:Marsupialia; D008969:Molecular Sequence Data; D009154:Mutation; D009381:Neoplasms, Radiation-Induced / Q000235:genetics*; D012513:Sarcoma, Experimental / Q000235:genetics*; D014466:Ultraviolet Rays
D018076:DNA, Complementary