Photoregulation of DNA photolyases in broom Sorghum seedlings

Using dark-grown 3 day-old Sorghum bicolor seedlings, photorepair of cyclob utane pyrimidine dimers (CPD) by CPD-photolyase and pyrimidine-(6-4)pyrimid inone photoproducts ([6-4]PP) by [6-4]PP-photolyase was studied in vivo and in vitro. The two types of DNA photoproducts were measured with specific m onoclonal antibodies. Sorghum seedlings have different photorepair enzymes for CPD and [6-4]PP. The CPD-photolyase was found to be increased in respon se to light with maximal efficiency in the UVA/blue spectral range, whereas [6-4]PP-photolyase was not influenced by light.