DNA repair in the metallothionein gene increases with transcriptional activation.

AUTOR(ES)

Okumoto, D S

RESUMO

We have studied DNA repair in the Chinese Hamster Ovary (CHO) metallothionein (MT) gene after UV-light induced damage. The repair was examined comparatively with or without transcriptional activation of the gene by incubation in the presence of the heavy metal ZnCl2. Whereas the repair efficiency was very low in the uninduced state, it increased significantly after induction of the gene. The presence of ZnCl2 did not appear to change other repair parameters in the cells. The overall genome DNA repair efficiency after UV irradiation was similar whether or not the gene was induced and the preferential DNA repair pattern in the essential dihydrofolate reductase (DHFR) gene which we have previously described was unaffected by the presence of ZnCl2. Based upon repair analysis in two different restriction fragments containing the MT I gene, we conclude that the region of efficient repair after induction is considerably larger than the 1 kb size of the gene. The results suggest that the accessibility of a genomic region to DNA repair enzymes may be regulated by the local chromatin structure in a dynamic manner.

Documentos Relacionados

• p53 oligomerization and DNA looping are linked with transcriptional activation.
• Differential repair of DNA damage in the human metallothionein gene family.
• The indirect association of human T-cell leukemia virus tax protein with DNA results in transcriptional activation.
• Stress-induced transcriptional activation.
• HMG1 interacts with HOX proteins and enhances their DNA binding and transcriptional activation.