Parental LTRs Are Important in a Construct of a Stable and Efficient Replication-Competent Infectious Molecular Clone of HIV-1 CRF08_BC

Qiwei Zhang,Xiaomin Zhang,Chengsong Wan,Donald Seto,Hao Wu,Bo-Jian Zheng,Hao-Jie Zhang,Zhiwei Chen,Xiao-Fang Yu

doi:10.1371/journal.pone.0031233

Qiwei Zhang, Xiaomin Zhang + Show 7 more

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https://doi.org/10.1371/journal.pone.0031233

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Abstract

Circulating recombinant forms (CRFs) of HIV-1 have been identified in southern China in recent years. CRF08_BC is one of the most predominant subtypes circulating in China. In order to study HIV subtype biology and to provide a tool for biotechnological applications, the first full-length replication-competent infectious molecular clone harboring CRF08_BC is reported. The construction of this clone pBRGX indicates that a moderate-copy number vector is required for its amplification in E. coli. In addition, it is shown that the parental CRF08_BC LTRs are important for generating this efficient replication-competent infectious clone. These observations may aid in the construction of infectious clones from other subtypes. Both the pBRGX-derived virus and its parental isolate contain CCR5 tropism. Their full-length genomes were also sequenced, analyzed, compared and deposited in GenBank (JF719819 and JF719818, respectively). The availability of pBRGX as the first replication-competent molecular clone of CRF08_BC provides a useful tool for a wide range of studies of this newly emergent HIV subtype, including the development of HIV vaccine candidates, antiviral drug screening and drug resistance analysis.

Highlights

Since the first report of an HIV-1 infection in Beijing in 1985 [1], HIV and its resultant disease, AIDS, have spread rapidly throughout the country and have become a major concern in China
As the pBRNG construct contains LTRs from pNL4-3 rather than from the primary isolate, these were exchanged with the ones from 2007CNGX-HK, resulting in clone pBRGX
Unlike pNGX5, both pBRNG and pBRGX constructs were stable in E. coli cultures, including strains DH5a and JM109, even after 20 passages of cultures

Summary

Introduction

Since the first report of an HIV-1 infection in Beijing in 1985 [1], HIV and its resultant disease, AIDS, have spread rapidly throughout the country and have become a major concern in China. The local epidemics of HIV-1 subtype B9 (Thai-B) in 1989 and subtype C in 1992, among intravenous drug users (IDUs) in Yunnan, triggered the explosive nation-wide HIV-1 epidemic in China [2,3]. The Circulating Recombinant Form (CRF) CRF08_BC presumably originated among IDUs in Yunnan, which is a major entry point for heroin smuggling into China, and likely spread along known drug trafficking routes to other districts, such as the Guangxi and Xinjiang regions of China in 1997 [5,6,7]. The Guangxi region, east Yunnan province (near Guangxi) and Liaoning province (northeastern China) have become three of the most heavily impacted populations in China due to this particular subtype [12,13,14]

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