The Streptomyces peucetius dpsY and dnrX Genes Govern Early and Late Steps of Daunorubicin and Doxorubicin Biosynthesis

Abstract

The Streptomyces peucetius dpsY and dnrXgenes govern early and late steps in the biosynthesis of the clinically valuable antitumor drugs daunorubicin (DNR) and doxorubicin (DXR). Although their deduced products resemble those of genes thought to be involved in antibiotic production in several other bacteria, this information could not be used to identify the functions ofdpsY and dnrX. Replacement of dpsYwith a mutant form disrupted by insertion of the aphIIneomycin-kanamycin resistance gene resulted in the accumulation of UWM5, the C-19 ethyl homolog of SEK43, a known shunt product of iterative polyketide synthases involved in the biosynthesis of aromatic polyketides. Hence, DpsY must act along with the other components of the DNR-DXR polyketide synthase to form 12-deoxyaklanonic acid, the earliest known intermediate of the DXR pathway. Mutation ofdnrX in the same way resulted in a threefold increase in DXR production and the disappearance of two acid-sensitive, unknown compounds from culture extracts. These results suggest thatdnrX, analogous to the role of the S. peucetius dnrH gene (C. Scotti and C. R. Hutchinson, J. Bacteriol. 178:7316–7321, 1996), may be involved in the metabolism of DNR and/or DXR to acid-sensitive compounds, possibly related to the baumycins found in many DNR-producing bacteria.

Daunorubicin efflux in Streptomyces peucetius modulates biosynthesis by feedback regulation

“…There is no BamHI site in the apramycin resistance gene and the next site is in the chromosome at a considerable distance from the cassette sequence. In this way, the junction region along with the neighboring drrD/dnrW (Lomovskaya et al, 1998) could be cloned. The resulting plasmid pRESAB (Fig.…”

Identification and Analysis of the Balhimycin Biosynthetic Gene Cluster and Its Use for Manipulating Glycopeptide Biosynthesis in Amycolatopsis mediterranei DSM5908

“…OrfXЈ showed the highest similarity to two gene products of the presumptive biosynthetic gene clusters of the glycopeptides A82846B (ORF14) and vancomycin of the A. orientalis (hydroxylase B) producer strains described above. Moreover, there is a high similarity to the daunorubicin-doxorubicin biosynthetic enzyme DnrX from Streptomyces peucetius (63% identity and 71% similarity over 113 aa), which was published recently (13). The exact role of DnrX in daunorubicin-doxorubicin biosynthesis remains unclear.…”

The Streptomyces peucetius dpsC Gene Determines the Choice of Starter Unit in Biosynthesis of the Daunorubicin Polyketide

“…The fact that S. lividans(pWHM1010) was able to incorporate the correct starter unit, propionyl-CoA, into these polyketides supports the belief that the dpsC and/or dpsD gene plays a role in the specification of the starter unit. Previous work by Lomovskaya et al (14) had shown that disruption of the dpsY gene in S. peucetius resulted in the production of UWM5 (Fig. 1B), an aberrantly cyclized 21-carbon compound, which led to the suggestion that dpsY maintains a role in the cyclization of the nascent polyketide backbone.…”

“…The plasmid pWHM75 (8) was used as the source of the dpsABCDEF genes. Plasmids pWHM346 (14) and pWHM555 (13) were used to obtain dpsY and dpsG, respectively. The plasmid pWHM1013, which is pGEM7zf (Promega, Madison, Wis.) containing the dpsBCDG genes, was created as described below and used as the starting point for constructing three other plasmids.…”