A histone H4 promoter for expression of a phleomycin-resistance gene in Phanerochaete chrysosporium

In this study, two transformation vectors (pMG101 and pMG103) for Phanerochaete chrysosporium were constructed, based on the ble phleomycin-resistance-encoding gene and a homologous histone H4 promoter. Transformation frequencies were 6–10 per μg of DNA. Transformed vector DNA could either exist as an unstable replicating plasmid or could be stably integrated. Integrated vector DNA from pMG101, which also contains a histone-encoding H3 gene in the promoter fragment, becomes methylated, resulting in inactivation of ble-dependent resistance. Plasmid pMG103, which lacks the H3, does not show methylation.