Changes in Parthenogenetic Imprinting Patterns during Reprogramming by Cell Fusion.

Hyun Sik Jang,Hyuk Song,Yean Ju Hong,Sang Jun Uhm,Hyun Woo Choi,Sung June Byun,Han Geuk Seo,Jeong Tae Do,Liangxue Lai

doi:10.1371/journal.pone.0156491

Abstract

Differentiated somatic cells can be reprogrammed into the pluripotent state by cell-cell fusion. In the pluripotent state, reprogrammed cells may then self-renew and differentiate into all three germ layers. Fusion-induced reprogramming also epigenetically modifies the somatic cell genome through DNA demethylation, X chromosome reactivation, and histone modification. In this study, we investigated whether fusion with embryonic stem cells (ESCs) also reprograms genomic imprinting patterns in somatic cells. In particular, we examined imprinting changes in parthenogenetic neural stem cells fused with biparental ESCs, as well as in biparental neural stem cells fused with parthenogenetic ESCs. The resulting hybrid cells expressed the pluripotency markers Oct4 and Nanog. In addition, methylation of several imprinted genes except Peg3 was comparable between hybrid cells and ESCs. This finding indicates that reprogramming by cell fusion does not necessarily reverse the status of all imprinted genes to the state of pluripotent fusion partner.

Highlights

Pluripotent stem cells can differentiate into all three germ layers in vitro and in vivo, and have unlimited capacity to self-renew [1,2,3]
62% (44/71) of parthenogenetic embryos progressed to blastocysts (Fig 1B). parthenogenetic ESCs (pESCs) derived from these parthenogenetic blastocysts were morphologically similar to biparental Embryonic stem cells (ESCs), and expressed alkaline phosphatase (Fig 1C) and pluripotency markers such as Oct4 and Nanog (Fig 1D)
These results indicate that ESCs derived from parthenogenetic blastocysts are similar to biparental ESCs

Summary

Introduction

Pluripotent stem cells can differentiate into all three germ layers in vitro and in vivo, and have unlimited capacity to self-renew [1,2,3]. Induced pluripotent stem cells (iPSCs) were generated from somatic cells by exogenous expression of defined transcription factors, including Oct, Sox, Klf, and c-Myc [10]. Reprogramming Alters Parthenogenetic Imprinting genes, differentiate into all three germ layers in vitro, generate germ-line chimeras [11], and, remarkably, confer pluripotency to somatic cells by cell-cell fusion [12]. Genomic imprinting and DNA methylation patterns form a gradient along the phases of migration. Reprogramming by transduction of defined factors modifies genomic imprinting, DNA methylation, and expression of imprinted genes [16]. We hypothesized that imprinting patterns of pluripotent fusion partners, ESCs or parthenogenetic ESCs (pESCs), dictate the imprinting patterns in the resulting hybrid cells

Materials and Methods

Results

Discussion