Genetic modification in the cyclin gene from a Nicotiana interspecific hybrid: role of the GTcyc gene in tumorization process

The organistic constitution of genetic tumors probably causes the constitue nt cells to undergo genetic change from normal growth to abnormal, a relati vely undifferentiated proliferation. We report here that the cyclin GTcyc g ene, isolated from genetic tumors yielded notably intense bands while those from the parental DNA were less expressed. In a similar fashion, Northern blot analysis revealed that the genetic tumors expressed high levels of GTc yc relative to non-tumor hybrid tissues. Furthermore, RAPD data showed that the genetic relationships between tumor tissues and their parents did not present a highly corresponding match, suggesting that tumor growth may rela te to the genetic modification or hybridization-related genome reorganizati on. Taken together, the cyclin gene performs a critical role in cell cycle progression, and this particular gene (GTcyc) may be a potential factor in tumor formations, resulting in gene alterations or gains, or changes to spe cific genomic regions.