# Expression and Localization of a New Parvovirus-Derived Protein in the Guinea Pig

## TL;DR

The study shows that a protein derived from an ancient virus in guinea pigs is expressed and located near microtubules in cells.

## Contribution

This is the second demonstration of an endogenous parvovirus-derived protein being expressed in vivo.

## Key findings

- The enRep-M9l protein is expressed in vivo and in guinea pig-derived JH4 cells.
- The enRep-M9l protein localizes to the cytoplasm near microtubules.
- The enRep-M9l gene is part of an endogenous parvoviral element in guinea pigs.

## Abstract

Endogenous viral elements (EVEs) are genomic sequences derived from viruses. Some EVEs have open reading frames (ORFs) that can express co-opted proteins in their host. Furthermore, some EVEs that are expressed as proteins have become part of cellular genes that are fusions of hosts and EVE sequences. Endogenous parvoviral elements (EPVs) are highly represented in mammalian genomes, and some of them contain ORFs and can be expressed as proteins. We have shown that an EPV containing an ORF is part of the guinea pig gene enRep-M9l. This gene is broadly transcribed in vivo, indicating that it can be translated into a protein. By generating antibodies against the enRep coding sequence of the enRep-M9l ORF, we showed that the protein enRep-M9l is expressed in vivo and in the guinea pig-derived cell line JH4. By immunofluorescence and in situ proximity ligation assays, we observed that enRep-M9l protein has a cytoplasmic localization near microtubules. The results of this study suggest that the guinea pig EPV-derived protein enRep-M9l is a microtubule-associated protein. To our knowledge, this is the second demonstration that an EPV-derived protein is expressed in vivo.