A human cellular sequence implicated in trk oncogene activation is DNA damage inducible.

Xeroderma pigmentosum cells, which are deficient in the repair of UV light-induced DNA damage, have been used to clone DNA-damage-inducible transcripts in human cells. The cDNA clone designated pC-5 hybridizes on RNA gel blots to a 1-kilobase transcript, which is moderately abundant in nontreated cells and whose synthesis is enhanced in human cells following UV irradiation or treatment with several other DNA-damaging agents. UV-enhanced transcription of C-5 RNA is transient and occurs at lower fluences and to a greater extent in DNA-repair-deficient than in DNA-repair-proficient cells. Southern blot analysis indicates that the C-5 gene belongs to a multigene family. A cDNA clone containing the complete coding sequence of C-5 was isolated. Sequence analysis revealed that it is homologous to a human cellular sequence encoding the amino-terminal activating sequence of the trk-2h chimeric oncogene [Kozma, S. C., Redmond, S. M. S., Xiao-Chang, F., Saurer, S. M., Groner, B. & Hynes, N. E. (1988) EMBO J. 7, 147-154]. The presence of DNA-damage-responsive sequences at the 5' end of a chimeric oncogene could result in enhanced expression of the oncogene in response to carcinogens.