Induced Pluripotent Stem Cells of Microtus levis x Microtus arvalis Vole Hybrids: Conditions Necessary for Their Generation and Self-Renewal

Every year, the list of mammalian species for which cultures of pluripotent stem cells (PSCs) are generated increases. PSCs are a unique tool for extending the limits of experimental studies and modeling different biological processes. In this work, induced pluripotent stem cells (iPSCs) from the hybrids of common voles Microtus levis and Microtus arvalis, which are used as model objects to study genome organization on the molecular-genetic level and the mechanisms of X-chromosome inactivation, have been generated. Vole iPSCs were isolated and cultured in a medium containing cytokine LIF, basic fibroblast growth factor (bFGF), ascorbic acid, and fetal bovine serum. Undifferentiated state of vole iPSCs is maintained by activation of their endogenous pluripotency genes - Nanog, Oct4, Sox2, Sall4, and Esrrb. The cells were able to maintain undifferentiated state for at least 28 passages without change in their morphology and give rise to three germ layers (ectoderm, mesoderm and endoderm) upon differentiation.

Intraspecific epigenetic polymorphism of the East European vole (Microtus levis Miller, 1908) in South-eastern Europe and Turkey

This study aims to represent the first report on population variation of 20 non-metric skull characters in East European vole (Microtus levis) from the Balkan (populations from Northern Dobruja; Southern Dobruja; East part of the Danube Plain; North-east Trace; Sofia field; South-east Trace) and Anatolian peninsulas (populations from North-west Anatolia region and Central Anatolia region), on the basis of which to determine its epigenetic variability and to analyse their mutual geographical epigenetic relations through comparison of the epigenetic divergence among them. Estimation of epigenetic variation of the studied populations of M. levis showed similar pattern of variation, but it is mostly higher than the other rodent species with a similar range of distribution, such as Microtus arvalis, Mus musculus, Apodemus sylvaticus, Apodemus flavicollis and Clethrionomys glareolus. Each one of the studied traits manifested some polymorphism. Moreover, all the calculated epigenetic distances (MMD) were statistically insignificant (P < 0.05) and epigenetic cranial uniqueness (MU) of any studied population was not found. These results reveal lack of expressed geographic relationship of population epigenetic variability in East European vole. The revealed populations epigenetic polymorphism of M. levis gives an opportunity for more complete assessment of variability and biological diversity of this species, but further research is necessary to elucidate its population epigenetics, especially as the data obtained in recent investigations of cranial morphology of the sibling species from the group the M. arvalis (sensu lato) added new locations to the distribution map of the East European vole in Eurasia.