Maurya & Rai (2017) Biotechnology International 10(2): 52-58
52
©Biotechnology Society www.bti.org.in
ISSN 0974-1453
Research article
CHICKEN ANEMIA VIRUS VP3 GENE CLONED IN pVAX1 VECTOR
CAUSES APOPTIC ACTIVITY IN HeLa CELLS
Raushi Maurya
1
and Anant Rai
2*
1
Department of Biotechnology, Mewar University, Chittorgarh, Rajasthan.
2
Institute of Biotechnology & IT, 197-198, Mudiya Ahmadnagar, Bareilly-2453122, UP.
*Corresponding author: raia48@gmail.com
ABSTRACT
VP3 protein gene of chicken anemia virus cloned in pVAX1 was analysed for its
apoptotic activity using HeLa cells in culture. It was found to produce high level of
apoptosis when analysed by DNA fragmentation assay, acridine orange-ethidium
bromide staining, caspase assay, annexin V binding assay, Tunel assay and MTT
cytotoxic assay.
Keywords: VP3, apoptin, pVAX1, caspase, annexin V binding.
INTRODUCTION
The 2.3 kb chicken anemia virus
(CAV) genome encodes three viral
proteins VP1, VP2, VP3. VP1 is major
capsid protein and VP2 is probably a non-
structural protein found in the cells in the
early stage of virus replication cycle
(Noteborn et al., 1995). VP1 and VP2 are
protective proteins that induce neutralising
antibodies (Kock et al., 1995). The third
viral protein VP3 is a 13 kDa protein that
shows apoptic activity and is able to
induce apoptosis within infected chicken
cells and human tumor cell lines (Noteborn
et al., 2004). VP3 has been shown to not
only induce apoptosis when introduced
into the precursors of chicken thymocytes,
but has been found to specifically kill
human cancer cells and transformed cells
without affecting the proliferation of
normal cells (Lee et al., 2012). Apoptin
causes apoptosis in various human tumors
and transformed cells (Danen Van
Oorschot et al., 1997). Apoptin is a
promising and ideal agent for cancer gene
therapy owing to its intrinsic specificity
and the inherent low toxicity (Gueden et
al., 2004). Because of its death inducing
abilities, the VP3 gene product was
renamed apoptin. Interestingly, the apoptic
activity of apoptin in not restricted to
chicken thymocytes (Danen Van Oorschot
et al., 1997). Unlike other tumor
suppressor or proapoptic genes, theapoptin
does not rely on the function of p53, BCL-
2, Bax, FADD, or Caspase-8 (Tavassoli et
al., 2005; Liu et al., 2006). Thus apoptin
may be used to treat a broad spectrum of
tumors that differ in mutational status of
p53 and the levels of expressions of
apoptotic regulators. The ability of apoptin
to induce apoptosis has been demonstrated
in more than 70 human cancer cell lines
(Backendorf et al., 2008; Noteborn et al.,