%0 Journal Article
%T Epigenetic reprogramming in the porcine germ line
%A Sara MW Hyldig
%A Nicola Croxall
%A David A Contreras
%A Preben D Thomsen
%A Ramiro Alberio
%J BMC Developmental Biology
%D 2011
%I BioMed Central
%R 10.1186/1471-213x-11-11
%X Our results show loss of DNA methylation in PGC colonizing the genital ridges. Analysis of IGF2-H19 regulatory region showed a gradual demethylation between E22-E42. In contrast, DMR2 of IGF2R was already demethylated in male PGC by E22. In females, IGF2R demethylation was delayed until E29-31, and was de novo methylated by E42. DNA repeats were gradually demethylated from E25 to E29-31, and became de novo methylated by E42. Analysis of histone marks showed strong H3K27me3 staining in migratory PGC between E15 and E21. In contrast, H3K9me2 signal was low in PGC by E15 and completely erased by E21. Cell cycle analysis of gonadal PGC (E22-31) showed a typical pattern of cycling cells, however, migrating PGC (E17) showed an increased proportion of cells in G2.Our study demonstrates that epigenetic reprogramming occurs in pig migratory and gonadal PGC, and establishes the window of time for the occurrence of these events. Reprogramming of histone H3K9me2 and H3K27me3 detected between E15-E21 precedes the dynamic DNA demethylation at imprinted loci and DNA repeats between E22-E42. Our findings demonstrate that major epigenetic reprogramming in the pig germ line follows the overall dynamics shown in mice, suggesting that epigenetic reprogramming of germ cells is conserved in mammals. A better understanding of the sequential reprogramming of PGC in the pig will facilitate the derivation of embryonic germ cells in this species.Primordial germ cells derived from the epiblast of pre-gastrulating embryos are the founder population of the future gametes. A unique attribute of PGC is the acquisition of totipotency, which is required for the generation of a new organism. Extensive epigenetic reprogramming of PGC underlies the capacity of these cells for acquiring totipotency [1,2]. Genome-wide DNA demethylation in mouse PGC results in the complete erasure of methylation marks in single-copy and imprinted genes, and a moderate reduction in retrotransposons and other repetitive ele
%U http://www.biomedcentral.com/1471-213X/11/11