Interactions of heterologous DNA with polyomavirus major structural protein, VP1

Abstract

Abstract`Empty' polyomavirus pseudocapsids, self-assembled from the major structural protein VP1, bind DNA nonspecifically and can deliver it into the nuclei of mammalian cells for expression [Forstova è et al. (1995) Hum. Gene Ther. 6, 2973 06]. Formation of suitable VP1-DNA complexes appears to be the limiting step in this route of gene delivery. Here, the character of VP1-DNA interactions has been studied in detail. Electron microscopy revealed that VP1 pseudocapsids can create in vitro at least two types of interactions with double-stranded DNA: (i) highly stable complexes, requiring free DNA ends, where the DNA is partially encapsidated; and, (ii) weaker interactions of pseudocapsids with internal parts of the DNA chain.z 1999 Federation of European Biochemical Societies.

Virus-like gene transfer into cells mediated by polyoma virus pseudocapsids

“…In contrast, pseudocapsids and empty capsids from a natural polyoma virus infection appear to interact with DNA by partially packaging it. 19,26 We therefore investigated whether pseudocapsid-mediated gene transfer depends on a specific packaging reaction.…”

“…18 These particles do not interact with exogenously added DNA in gel shift assays and when observed by electron microscopy ( Figure 1B, panel a) they do not form stable interactions with plasmid DNA, in contrast to 'empty pseudocapsids' (panel b; plasmid DNA alone is shown in panel c). 19 Heavy pseudocapsids exhibited little or no DNA transfer activity when mixed with EGFP DNA and tested in the cos cell assay, in contrast to empty pseudocapsids, which gave more than a 10-fold increase in gene transfer efficiency compared with DNA alone ( Figure 1C). These results confirm that a specific packaging reaction is required to form complexes of pseudocapsids and DNA capable of mediating DNA transfer.…”

“…9,18,19 Furthermore, VLPs composed of mouse polyoma virus VP1 (called pseudocapsids) can transfer plasmid DNA to cells, resulting in heterologous gene expression both in vitro and in vivo. [20][21][22] DNA transfer in vitro has also been reported for a number of other VLPs, including those derived from human polyoma and papilloma viruses.…”

Efficient gene transfer using the human JC virus-like particle that inhibits human colon adenocarcinoma growth in a nude mouse model

“…28 Another DNA packaging method based on capsomere reassembly has been shown to have low efficiency in terms of gene transduction because capsomere aggregation occurs during the process of assembly. 29,30 These limitations on the use of polyomavirus vectors because of problems with packaging DNA molecules need to be addressed.…”

Scanning surface confocal microscopy for simultaneous topographical and fluorescence imaging: Application to single virus-like particle entry into a cell

“…Polyoma VLPs are nanospheres composed of 360 molecules of a single viral coat protein, VP1, that have been shown to interact with and carry plasmid DNA into cells (12,13). The protein nanospheres encapsidate 1-2 kb of the plasmid DNA whereas the remainder loosely associates with the outside of the VLP structure (14,15). These particles enter cells by both receptor-dependent and -independent routes, but only the former is productive for gene transfer (16).…”