Transcriptomic analysis of CYP genes in Rhizopus nigricans and identification of the steroid 11α-hydroxylase candidate genes

Abstract

Filamentous fungus Rhizopus nigricans is used commercially for steroid 11α-hydroxylation reactions to prepare key steroid intermediates in the synthesis of a variety of steroid drugs. Although it has been previously established that the enzyme involved in steroid 11α-hydroxylation is a cytochrome P450 protein, the corresponding encoding gene remains elusive. In the present study, steroid 11α-hydroxylase activities in strain R. nigricans TCCC 41047 were shown to be expressed only under substrate induction. Transcriptome sequencing was conducted to establish the list of the cytochrome P450 genes (CYP) expressed in TCCC41047 under substrate induction. The results revealed that 14 CYP genes were expressed under induction conditions. Furthermore, qRT-PCR showed that the transcription of 3 CYP genes was highly induced by steroid substrate EP and thus identified as candidate genes for encoding the target 11α-hydroxylase gene and pave the way for the engineering of highly candidate genes will aid in the cloning and characterization of the target steroid 11α-hydroxylase gene and pave the way for the engineering of highly efficient production strains for preparing valuable steroid 11α-hydroxylation derivatives.