| Abstract [eng] |
In our laboratory's previous studies, using next-generation sequencing methods to examine kidney DNA samples from the striped field mice (Apodemus agrarius), a non-canonical genome organization (NGO) polyomavirus (PyV) sequence was identified and named AagraPyV. This sequence is characterized by early and late gene homologues encoded in the same direction, whereas in PyV genomes they are usually encoded in the opposite directions. To our knowledge, this is the first and so far the only NGO PyV sequence identified in a tissue sample from a specific organism. The AagraPyV sequence is phylogenetically very distant from mammalian PyVs, so it is unclear whether the natural host of AagraPyV is A. agrarius mice. In order to investigate this in the future, this work examined the ability of AagraPyV structural proteins to assemble into virus-like particles (VLPs) in S. cerevisiae yeast, so that in case of VLP formation, they could later be used as antigens in serological experiments. Considering the unusually elongated C-terminal region of the putative VP1 protein (VP1-Pilnas1), assembly into VLPs was investigated either by expressing VP1-Pilnas1 or its predicted splicing variants (VP1-930 and VP1-1168). In none of these cases was there any clear signs of VP1 protein expression and assembly into VLPs. However, the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transmission electron microscopy (TEM) analysis of the VP1-930 variant sample showed possible signs of VLPs formation. Co-expression of the VP1-930 variant with individual AagraPyV proteins or MarPyV2 sTAg did not improve VP1-930 protein assembly into VLPs. In addition, a total of eleven distinct AagraPyV genome sequences were identified from A. agrarius kidney DNA samples in this study. They differed from each other by 93,1 %, which is less than is usually described for variants of the same PyV species. The putative LTAg proteins of all AagraPyV sequences contained altered conserved motifs, which supports the hypothesis raised in the previous studies that AagraPyV sequences may have originated not from A. agrarius mice, but from their parasites. |
