Improvement of oxytetracycline production mediated via cooperation of resistance genes in Streptomyces rimosus

Abstract

Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics. To increase the oxytetracycline (OTC) production in Streptomyces rimosus, we investigated the cooperative effect of three co-overexpressing OTC resistance genes: one gene encodes a ribosomal protection protein (otrA) and the other two express efflux proteins (otrB and otrC). Results indicated that combinational overexpression of otrA, otrB, and otrC (MKABC) exerted a synergetic effect. OTC production increased by 179% in the recombinant strain compared with that of the wild-type strain M4018. The resistance level to OTC was increased by approximately two-fold relative to the parental strain, thereby indicating that applying the cooperative effect of self-resistance genes is useful to improve OTC production. Furthermore, the previously identified cluster-situated activator OtcR was overexpressed in MKABC in constructing the recombinant strain MKRABC; such strain can produce OTC of approximately 7.49 g L, which represents an increase of 19% in comparison with that of the OtcR-overexpressing strain alone. Our work showed that the cooperative overexpression of self-resistance genes is a promising strategy to enhance the antibiotics production in Streptomyces.

Impact of otrA expression on morphological differentiation, actinorhodin production, and resistance to aminoglycosides in Streptomyces coelicolor M145

“…Interestingly, in contrast to the 16S rRNA gene, the regulatory gene actII-orf4 was much more strongly expressed under the influence of otrA indicating a more specific function towards the natural product biosynthesis of our protein. Our results are in accordance with the results of Yin et al (2017), who reported that otrA over-expression rather than that of otrB and otrC in S. rimosus M4018 exhibits effects on OTC production. Surprisingly, overexpression of otrA in S. rimosus M527 had no effect on OTC production (data not shown), although it caused acceleration of morphological development (Fig.…”

“…OTRA confers OTC resistance by interacting with the ribosome and dislodging the bound OTC in a GTP-binding and hydrolysis-dependent manner (Mak et al, 2014). It has been described that the introduction of the otrA gene could enhance the host's resistance to OTC (Binnie et al, 1989;Doyle et al, 1991;Yin et al, 2017). In our study we showed that S. coelicolor M145-OA exhibited higher resistance to OTC than the control strain M145.…”

The Antitumor Agent Ansamitocin P-3 Binds to Cell Division Protein FtsZ in Actinosynnema pretiosum

“…In this study, it was observed that exogenous AP-3 at a concentration higher than 300 mg/L caused severe inhibition on the growth of WXR-24 ( Figure 1c and Table S2). Improving strain resistance has been widely used to enhance the yields of various antibiotics, such as oxytetracycline [28], doxorubicin [29], rimocidin [30], daptomycin [31] and toyocamycin [32]. However, these strategies mainly focus on overexpressing efflux genes or engineering resistance genes.…”

Regulation of antibiotic biosynthesis in actinomycetes: Perspectives and challenges

“…Recently, there has been considerable interest in rational engineering of antibiotic producers. Improvement of antibiotic titers can be achieved by overexpression of key structural genes [ 69 ], resistance genes [ 70 ], ATP-binding cassette transporter genes [ 71 ] or amplification of the entire BGCs [ [72] , [73] , [74] , [75] , [76] ].…”