Metagenomic Analysis of Apple Orchard Soil Reveals Antibiotic Resistance Genes Encoding Predicted Bifunctional Proteins
Metagenomic Analysis of Apple Orchard Soil Reveals Antibiotic Resistance Genes Encoding Predicted Bifunctional Proteins
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DOI：
10.1128/aem.01763-09
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发表时间：
2010-07-01
影响因子：
4.4
通讯作者：
Handelsman, Jo
中科院分区：
文献类型：
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作者：
Donato, Justin J.;Moe, Luke A.;Handelsman, Jo
为了深入了解抗生素抗性基因的多样性和起源，我们使用功能元基因组学在一个苹果园的土壤中鉴定了抗性基因，这包括将大段外源DNA插入到大肠杆菌中，并对所得到的克隆进行表达功能的分析。在13个耐药克隆中，我们发现了两个编码双功能蛋白的基因。一种预测的双功能蛋白对头孢他啶具有耐药性，并包含预测的转录调节因子和β-内酰胺酶之间的自然融合。对编码预测的双功能β-内酰胺酶的整个元基因组克隆的序列分析显示，一个可能与氯霉素耐药性有关的基因以及一个预测的转座酶。第二个克隆编码预测的双功能蛋白，对卡那霉素产生抗性，并包含一个氨基糖苷乙酰基转移酶结构域，与第二个乙酰基转移酶结构域融合，根据核苷酸序列，该结构域被预测不参与抗生素耐药性。这是首次报道转录调节因子与β-内酰胺酶融合，以及氨基糖苷乙酰转移酶与不参与抗生素耐药性的乙酰转移酶融合。
To gain insight into the diversity and origins of antibiotic resistance genes, we identified resistance genes in the soil in an apple orchard using functional metagenomics, which involves inserting large fragments of foreign DNA into Escherichia coli and assaying the resulting clones for expressed functions. Among 13 antibiotic-resistant clones, we found two genes that encode bifunctional proteins. One predicted bifunctional protein confers resistance to ceftazidime and contains a natural fusion between a predicted transcriptional regulator and a beta-lactamase. Sequence analysis of the entire metagenomic clone encoding the predicted bifunctional beta-lactamase revealed a gene potentially involved in chloramphenicol resistance as well as a predicted transposase. A second clone that encodes a predicted bifunctional protein confers resistance to kanamycin and contains an aminoglycoside acetyltransferase domain fused to a second acetyltransferase domain that, based on nucleotide sequence, was predicted not to be involved in antibiotic resistance. This is the first report of a transcriptional regulator fused to a beta-lactamase and of an aminoglycoside acetyltransferase fused to an acetyltransferase not involved in antibiotic resistance.