Two distinct amplification events of the c-myc locus in a colorectal tumour.
Southern hybridisation of genomic DNA extracted from a human primary colorectal carcinoma revealed amplification of a fragment containing the wild-type c-myc locus. Two additional rearranged DNA fragments, lying upstream of c-myc, fused to distant non-contiguous sequences from the same chromosome, with an opposite configuration (head to head vs. head to tail), were also found to be amplified. Sequences analysis suggested that these rearrangements resulted from illegitimate recombination at two distinct points within the DNA sequence just upstream of the c-myc ORF and further that these events triggered two different amplification mechanisms, only one of which, involving a strand invasion event following DNA double strand breaks, increased the copy number of the c-myc ORF.
La Farina
Mario
M
Department of Cellular and Developmental Biology, University of Palermo, Palermo, Italy. mariolaf@unipa.it
Bellavia
Maurizio
M
Tagliavia
Marcello
M
Eterno
Vincenzo
V
Colomba
Paolo
P
Scibetta
Angelo
A
Albanese
Ida
I
D001483:Base Sequence; D015139:Blotting, Southern; D015179:Colorectal Neoplasms / Q000235:genetics*; D005784:Gene Amplification; D016259:Genes, myc; D006801:Humans; D008969:Molecular Sequence Data