The effect of interspecific oocytes on demethylation of sperm DNA.
In contrast to mice, in sheep no genome-wide demethylation of the paternal genome occurs within the first postfertilization cell cycle. This difference could be due either to an absence of a sheep demethylase activity that is present in mouse ooplasm or to an increased protection of methylated cytosine residues in sheep sperm. Here, we use interspecies intracytoplasmic sperm injection to demonstrate that sheep sperm DNA can be demethylated in mouse oocytes. Surprisingly, mouse sperm can also be demethylated to a limited extent in sheep oocytes. Our results suggest that the murine demethylation process is facilitated either by a sperm-derived factor or by male pronuclear chromatin composition.
Beaujean
Nathalie
N
Division of Gene Expression and Development, Roslin Institute, Roslin EH25 9PS, United Kingdom.
Taylor
Jane E
JE
McGarry
Michelle
M
Gardner
John O
JO
Wilmut
Ian
I
Loi
Pasqualino
P
Ptak
Grazyna
G
Galli
Cesare
C
Lazzari
Giovanna
G
Bird
Adrian
A
Young
Lorraine E
LE
Meehan
Richard R
RR
D000818:Animals; D004247:DNA / Q000378:metabolism*; D019175:DNA Methylation; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D009865:Oocytes / Q000378:metabolism*; D012756:Sheep / Q000235:genetics*; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000378:metabolism*
D004247:DNA