Differential regulation of maternal and paternal chromosome condensation in mitotic zygotes.
A-kinase anchoring protein AKAP95 is implicated in somatic mitotic chromosome condensation by recruiting the condensin complex. Here, we report a differential regulation of condensation of maternal and paternal chromosomes mediated by AKAP95 in mitotic mouse zygotes. AKAP95 is synthesized upon oocyte activation, targeted to the female pronucleus and specifically associates with maternal chromosomes at mitosis. AKAP95 mRNA is highly restricted to the vicinity of the meiotic spindle in metaphase II oocytes. In vivo displacement of endogenous AKAP95 in female pronuclei by microinjection of competitor peptides and rescue experiments show that AKPA95 is required for recruitment of the mCAP-D2 condensin subunit to, and condensation of, maternal chromosomes. In contrast, AKAP95 is dispensable for mCAP-D2 recruitment to, and condensation of, paternal chromosomes. Our results indicate that at first embryonic mitosis, paternal chromosomes target condensins and condense independently of AKAP95, whereas maternal chromosomes require AKAP95 for condensin recruitment and condensation. We propose a concept whereby condensation of chromosomes in gametes, zygotes and somatic cells involves related but distinct mechanisms.
Bomar
Jacqueline
J
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst 01003, USA.
Moreira
Pedro
P
Balise
John J
JJ
Collas
Philippe
P
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001757:Blastomeres / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D002875:Chromosomes / Q000235:genetics* / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D008938:Mitosis / Q000187:drug effects / Q000235:genetics*; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010063:Ovum / Q000378:metabolism*; D010446:Peptide Fragments; D000075223:Poly-ADP-Ribose Binding Proteins; D011247:Pregnancy; D012737:Sex Factors; D013094:Spermatozoa / Q000378:metabolism*; D015053:Zygote / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism
C490117:AKAP8L protein, human; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; C413383:NCAPD2 protein, human; D009687:Nuclear Proteins; D010446:Peptide Fragments; D000075223:Poly-ADP-Ribose Binding Proteins; C108312:condensin complexes; D017868:Cyclic AMP-Dependent Protein Kinases; D000251:Adenosine Triphosphatases