Modulation of imprinted gene network in placenta results in normal development of in vitro manipulated mouse embryos.
Genomic imprinting regulates the expression of a group of genes monoallelically expressed in a parent-of-origin specific manner. Allele-specific DNA methylation occurs at differentially methylated regions (DMRs) of these genes. We have previously shown that in vitro fertilization and embryo culture result in methylation defects at the imprinted H19-Igf2 locus at the blastocyst stage. The current study was designed to evaluate the consequences of these manipulations on genomic imprinting after implantation in the mouse. Blastocysts were produced following three experimental conditions: (i) embryos maintained in culture medium after in vivo fertilization or (ii) in vitro fertilization and (iii) a control group with embryos obtained after in vivo fertilization and timed mating. Blastocysts were all transplanted into pseudopregnant females. Embryos and placentas were collected on day 10.5 of development. DNA methylation patterns of the H19, Igf2, Igf2r and Dlk1-Dio3 DMRs were analyzed by quantitative pyrosequencing. In contrast to blastocyst stage, methylation profiles were normal both in embryonic and placental tissues after in vitro fertilization and culture. Expression of a selected set of imprinting genes from the recently described imprinted gene network (IGN) (including Igf2 and H19) was analyzed in placental tissues by quantitative RT-PCR. Placentas obtained after in vitro fertilization and embryo culture displayed significantly disturbed levels of H19 and Igf2 mRNA, as well as of most other genes from the IGN. As embryos were phenotypically normal, we hypothesize that the modulation of a coordinated network of imprinted genes results in a compensatory process capable of correcting potential dysfunction of placenta.
Biology of Reproduction, Hospital Cochin, Paris, France patricia.fauque@cch.aphp.fr
Patricia
P
Fauque
Marie-Anne
MA
Ripoche
Jörg
J
Tost
Laurent
L
Journot
Anne
A
Gabory
Florence
F
Busato
Anne
A
Le Digarcher
Françoise
F
Mondon
Ivo
I
Gut
Pierre
P
Jouannet
Daniel
D
Vaiman
Luisa
L
Dandolo
Hélène
H
Jammes
D000818:Animals; D019175:DNA Methylation / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D040461:Gene Components; D053263:Gene Regulatory Networks / Q000235:genetics / Q000502:physiology*; D018392:Genomic Imprinting / Q000235:genetics / Q000502:physiology*; D066298:In Vitro Techniques; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D051379:Mice; D010920:Placenta / Q000196:embryology*; D011247:Pregnancy; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
C094335:H19 long non-coding RNA; C513121:IGF2 protein, mouse; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II