BACKGROUND Aerobic side chain degradation of phytosterols by actinobacteria is the basis for the industrial production of androstane steroids which are the starting materials for the synthesis of steroid hormones. A native strain of Mycobacterium sp. VKM Ac-1817D effectively produces 9α-hydroxyandrost-4-ene-3,17-dione (9-OH-AD) from phytosterol, but also is capable of slow steroid core degradation. However, the set of the genes with products that are involved in phytosterol oxidation, their organisation and regulation remain poorly understood. RESULTS High-throughput sequencing of the global transcriptomes of the Mycobacterium sp. VKM Ac-1817D cultures grown with or without phytosterol was carried out. In the presence of phytosterol, the expression of 260 genes including those related to steroid catabolism pathways significantly increased. Two of the five genes encoding the oxygenase unit of 3-ketosteroid-9α-hydroxylase (kshA) were highly up-regulated in response to phytosterol (55- and 25-fold, respectively) as well as one of the two genes encoding its reductase subunit (kshB) (40-fold). Only one of the five putative genes encoding 3-ketosteroid-∆1-dehydrogenase (KstD_1) was up-regulated in the presence of phytosterol (61-fold), but several substitutions in the conservative positions of its product were revealed. Among the genes over-expressed in the presence of phytosterol, several dozen genes did not possess binding sites for the known regulatory factors of steroid catabolism. In the promoter regions of these genes, a regularly occurring palindromic motif was revealed. The orthologue of TetR-family transcription regulator gene Rv0767c of M. tuberculosis was identified in Mycobacterium sp. VKM Ac-1817D as G155_05115. CONCLUSIONS High expression levels of the genes related to the sterol side chain degradation and steroid 9α-hydroxylation in combination with possible defects in KstD_1 may contribute to effective 9α-hydroxyandrost-4-ene-3,17-dione accumulation from phytosterol provided by this biotechnologically relevant strain. The TetR-family transcription regulator gene G155_05115 presumably associated with the regulation of steroid catabolism. The results are of significance for the improvement of biocatalytic features of the microbial strains for the steroid industry.

中文翻译：

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全基因组对植物甾醇的分枝杆菌产生9-羟基雄烯二酮菌株的反应。VKM Ac-1817D。

背景技术放线菌对植物甾醇的需氧侧链降解是工业生产雄甾烷类固醇的基础，雄甾烷类固醇是合成类固醇激素的起始材料。分枝杆菌属的天然菌株。VKM Ac-1817D可从植物甾醇有效产生9α-羟基雄烷-4-烯-3,17-二酮（9-OH-AD），但也能减缓类固醇核心降解。但是，人们对与植物甾醇氧化有关的基因及其产物的组织和调控的了解仍然很少。结果分枝杆菌总转录组的高通量测序。进行有或没有植物甾醇生长的VKM Ac-1817D培养。在存在植物甾醇的情况下，包括与类固醇分解代谢途径有关的基因在内的260个基因的表达显着增加。编码3-酮类固醇9α-羟化酶（kshA）加氧酶单元的五个基因中的两个被上调，分别响应植物甾醇（分别为55倍和25倍）以及编码其还原酶的两个基因之一亚基（kshB）（40倍）。在存在植物甾醇的情况下，编码3-酮类固醇-∆1-脱氢酶（KstD_1）的五个推定基因中只有一个被上调（61倍），但在其产物的保守位置上发现了数个替代。在存在植物甾醇的情况下过表达的基因中，数十个基因不具有类固醇分解代谢的已知调节因子的结合位点。在这些基因的启动子区域，揭示了定期发生的回文基序。M.的TetR家族转录调节基因Rv0767c的直系同源物。在分枝杆菌属中鉴定出结核病。VKM Ac-1817D为G155_05115。结论与固醇侧链降解和类固醇9α-羟基化相关的基因的高表达水平，加上KstD_1可能存在的缺陷，可能有助于该生物技术从植物甾醇中有效地积累9α-羟基雄烷-4-烯-3,17-二酮。相关应变。TetR家族转录调节基因G155_05115可能与类固醇分解代谢的调节有关。这些结果对于改善甾体行业微生物菌株的生物催化特性具有重要意义。结论与固醇侧链降解和类固醇9α-羟基化相关的基因的高表达水平，加上KstD_1可能存在的缺陷，可能有助于由该生物技术提供的植物固醇有效的9α-羟基雄烷-4-烯-3,17-二酮积聚。相关应变。TetR家族转录调节基因G155_05115可能与类固醇分解代谢的调节有关。这些结果对于改善甾体行业微生物菌株的生物催化特性具有重要意义。结论与固醇侧链降解和类固醇9α-羟基化相关的基因的高表达水平，加上KstD_1可能存在的缺陷，可能有助于由该生物技术提供的植物固醇有效的9α-羟基雄烷-4-烯-3,17-二酮积聚。相关应变。TetR家族转录调节基因G155_05115可能与类固醇分解代谢的调节有关。这些结果对于改善甾体行业微生物菌株的生物催化特性具有重要意义。