Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Virol. Feb 12, 2017; 6(1): 17-25
Published online Feb 12, 2017. doi: 10.5501/wjv.v6.i1.17
Expression of hepatitis B virus surface antigens induces defective gonad phenotypes in Caenorhabditis elegans
Yi-Yin Chen, Li-Wei Lee, Wei-Ning Hong, Szecheng J Lo
Yi-Yin Chen, Li-Wei Lee, Szecheng J Lo, Department of Biomedical Science, College of Medicine, Chang Gung University, Tao Yuan 333, Taiwan
Yi-Yin Chen, Wei-Ning Hong, Szecheng J Lo, Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Tao Yuan 333, Taiwan
Author contributions: Chen YY, Lee LW and Lo SJ conceived and designed experiments; Chen YY, Lee LW and Hong WN performed the experiments; Chen YY and Lo SJ analyzed data; Lee LW and Lo SJ wrote the paper.
Supported by Chang Gung Memorial Hospital, grants Nos. CMRPD1C0812, CMRPD1C0813 and BMRP742 (to Lo SJ).
Institutional review board statement: No.
Informed consent statement: No.
Conflict-of-interest statement: The authors declare no conflict of interest.
Data sharing statement: No.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Szecheng J Lo, PhD, Professor, Department of Biomedical Science, College of Medicine, Chang Gung University, #259 Wen-Hwa 1st Road, Tao Yuan 333, Taiwan.
Telephone: +886-3-2118800-3259 Fax: +886-3-2118392
Received: June 24, 2016
Peer-review started: June 27, 2016
First decision: September 5, 2016
Revised: October 9, 2016
Accepted: November 27, 2016
Article in press: November 29, 2016
Published online: February 12, 2017

To test whether a simple animal, Caenorhabditis elegans (C. elegans), can be used as an alternative model to study the interaction between hepatitis B virus antigens (HBsAg) and host factors.


Three plasmids that were able to express the large, middle and small forms of HBsAgs (LHBsAg, MHBsAg, and SHBsAg, respectively) driven by a ubiquitous promoter (fib-1) and three that were able to express SHBsAg driven by different tissue-specific promoters were constructed and microinjected into worms. The brood size, egg-laying rate, and gonad development of transgenic worms were analyzed using microscopy. Levels of mRNA related to endoplasmic reticulum stress, enpl-1, hsp-4, pdi-3 and xbp-1, were determined using reverse transcription polymerase reaction (RT-PCRs) in three lines of transgenic worms and dithiothreitol (DTT)-treated wild-type worms.


Severe defects in egg-laying, decreases in brood size, and gonad retardation were observed in transgenic worms expressing SHBsAg whereas moderate defects were observed in transgenic worms expressing LHBsAg and MHBsAg. RT-PCR analysis revealed that enpl-1, hsp-4 and pdi-3 transcripts were significantly elevated in worms expressing LHBsAg and MHBsAg and in wild-type worms pretreated with DTT. By contrast, only pdi-3 was increased in worms expressing SHBsAg. To further determine which tissue expressing SHBsAg could induce gonad retardation, we substituted the fib-1 promoter with three tissue-specific promoters (myo-2 for the pharynx, est-1 for the intestines and mec-7 for the neurons) and generated corresponding transgenic animals. Moderate defective phenotypes were observed in worms expressing SHBsAg in the pharynx and intestines but not in worms expressing SHBsAg in the neurons, suggesting that the secreted SHBsAg may trigger a cross-talk signal between the digestive track and the gonad resulting in defective phenotypes.


Ectopic expression of three forms of HBsAg that causes recognizable phenotypes in transgenic worms suggests that C. elegans can be used as an alternative model for studying virus-host interactions because the resulting phenotype is easily detected through microscopy.

Keywords: Hepatitis B virus, Caenorhabditis elegans, Green fluorescence proteins, Endoplasmic reticulum stress, Gonad retardation, Surface antigens

Core tip: In the past, mouse and cell culture models have been used for studying the effects of hepatitis B virus antigens (HBsAg) on hosts. Both models have advantages and disadvantages in terms of economic and time concerns. In this study, we provide an alternative animal model, Caenorhabditis elegans (C. elegans), to demonstrate that SHBsAg can induce observable phenotypes which has never been reported in mouse and cell culture models. We suggest that C. elegans can serve as a new plateform for studying various viral pathogenesis.