Isolation of the rat s-myc gene having tumor suppressing activity

We have isolated a myc related gene, called s-myc, from a rat genomic library using a 32P-labeled fragment of exon 3 of v-myc as a probe. Nucleotide sequencing showed that the s-myc gene contains an open reading frame of 1,287 bp without introns. The s-Myc protein predicted from the DNA sequence has approximately 60% amino acid sequence homology with that of the mouse N-Myc protein. Transfection of the s-myc gene into rat RT4-AC tumor cells induced morphological changes of the cells and suppressed their tumorigenicity in nude mice.