Characterization of a Neurospora crassa photolyase-deficient mutant generated by repeat induced point mutation of the phr gene

We produced a photolyase-deficient mutant by repeat induced point mutation using the Neurospora crassa photolyase gene cloned previously, This mutatio n identified a new gene, phr, which was mapped on the right arm of linkage group I by both RFLP mapping and conventional mapping. To investigate the r elationship between photoreactivation and dark repair processes, especially excision repair, double mutants of phr with representative repair-defectiv e mutants of different types were constructed and tested for UV sensitivity and photoreactivation. The results show that the phr mutation has no influ ence on dark repair, Tests with CPD and TC(6-4) photoproduct-specific antib odies demonstrated that the phr mutant is defective in CPD photolyase and c onfirmed that there is no TC(6-4) photolyase activity in N, crassa. Further more, N, crassa photolyase is not a blue light receptor in the signal trans duction that induces carotenoid biosynthesis, (C) 1999 academic Press.