Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Genomics and Improvement Laboratory » Research » Publications at this Location » Publication #317031
Title: Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells

Author
item BERMEJO-ALVAREZ, P - University Of Maryland
item RAMOS-IBEAS, P - Instituto Nacional De Investigacion Y Technologia Agraria Y Alimentaria
item PARK, KI-EUN - University Of Maryland
item Powell, Anne
item VANSANDT, LINDSEY - University Of Maryland
item Bickhart, Derek
item RAMIREZ, M - Instituto Nacional De Investigacion Y Technologia Agraria Y Alimentaria
item GUTIERREZ-ADAN, A - Instituto Nacional De Investigacion Y Technologia Agraria Y Alimentaria
item TELUGU, BHANU - University Of Maryland

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2015
Publication Date: 9/2/2015
Citation: Bermejo-Alvarez, P., Ramos-Ibeas, P., Park, K., Powell, A.M., Vansandt, L., Bickhart, D.M., Ramirez, M.A., Gutierrez-Adan, A., Telugu, B. 2015. Tet-mediated imprinting erasure in H19 locus following reprogramming of spermatogonial stem cells to induced pluripotent stem cells. Scientific Reports. 5:13691.

Interpretive Summary: Epigenetic marks -- or chemical tags placed on DNA that play a large role in development -- are often erased shortly after the zygote is formed from sperm and egg. This project identified the timing of this erasure for parent-specific epigenetic marks by using knockout mice and induced stem cell formation from sperm cells. Due to changes in gene expression and detection of different epigenetic marks in the samples, it was determined that parent-specific epigenetic marks occur late in development.

Technical Abstract: Selective methylation of CpG islands at imprinting control regions (ICR) determines the monoparental expression of a subset of genes. The imprinting marks are protected from global demethylation taking place during pre-implantation development before being reset in primordial germ cells. However, it is unclear whether artificial reprogramming induced by the ectopic expression of Yamanaka factors disrupts these marks and whether cell type of origin affects the dynamics of reprogramming. In this study, spermatogonial stem cells (SSC) that harbor paternalized imprinting marks that are distinct from somatic fibroblast cells were reprogrammed to iPSC (SSCiPSC and fiPSC respectively). The SSCiPSC were able to form teratomas and generated chimeras with a higher skin chimerism than those derived from fiPSC. RNA-seq analysis confirmed extensive reprogramming at the transcriptional level with 12051 genes differentially expressed between SSC and SSCiPSC and only 665 between SSCiPSC and fiPSC. Reprogramming of SSC affected 24 of 41 imprinting gene clusters known in the mouse genome. A closer look at H19 ICR revealed complete erasure in SSCiPSC (68 % in SSC vs 0-2 % in SSCiPSC), which was maintained even after in vivo differentiation in contrast to fiPSC (48 % in fibroblast vs 20-39.3 % in fiPSC). Reprogramming of SSC from Tet1 and Tet2 double knockout mice however lacked demethylation of H19 ICR (43-70 %). These results signify that imprinting erasure is a late event during reprogramming primarily mediated by Tets and also depends on the epigenetic landscape of the genome of the precursor cell.