Near-ultraviolet radiation blocks SOS responses to DNA damage in Escherichia coli
✍ Scribed by Turner, Mary A. ;Eisenstark, A.
- Book ID
- 104723472
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 479 KB
- Volume
- 193
- Category
- Article
- ISSN
- 0026-8925
No coin nor oath required. For personal study only.
✦ Synopsis
Escherichia coli cells in which the recA promoter is fused to a lac structural gene, (Mu) Mud(Ap,lac)::rec, were irradiated with two far-ultraviolet light wavelengths (254 and 290 nm), selected monochromatic near-ultraviolet (NUV) wavelengths 313 nm, 334 nm, 365 nm, or broad band solar-UV (290-420 nm) from a solar simulator. Irradiation with the two far-ultraviolet wavelengths was followed by high yields of beta-galactosidase, lambda prophage induction, and Weigle reactivation. These end points were not observed after irradiation with the selected NUV wavelengths or the broad spectrum solar-UV. Thus, neither broad spectrum solar-UV nor monochromatic NUV wavelengths resulted in the derepression of the recA promoter. Further, prior exposure of the cells either to the selected monochromatic NUV wavelengths or to solar-UV inhibited (a) the induction of beta-galactosidase by subsequent 254-nm radiation, (b) subsequent 254-nm induction of lambda prophage, (c) Weigle reactivation, and (d) mutation frequency. These observations are consistent with the hypothesis that NUV blocks subsequent recA protease action.