Partially functional Cenpa-GFP fusion protein causes increased chromosome missegregation and apoptosis during mouse embryogenesis.
CENP-A is an essential histone H3-like protein that localizes to the centromeric region of eukaryotic chromosomes. Heterozygous and homozygous Cenpa-GFP fusion-protein mouse mutants, generated through targeted insertion of the green fluorescent protein (GFP) gene into the mouse Cenpa gene locus, show specific localized fluorescence at all the centromeres. Heterozygous mice are healthy and fertile. Cenpa-GFP homozygotes (Cenpag/g) undergo many cell divisions, giving rise to up to one million cells that show relatively accurate differentiation into distinct mouse embryonic tissues until day 10.5 when significant levels of chromosome missegregation, aneuploidy and apoptosis result in death. Cenpag/g embryos assemble functional kinetochores that bind to a host of centromere-specific structural and mitotic spindle checkpoint proteins (Cenpc, BubR1, Mad2 and Zw10). Examination of the nucleosomal phasing of centromeric minor and pericentromeric major satellite sequences indicates that the formation of Cenpag/g homotypic nucleosomes is not accompanied by any overt alteration to the overall size of the monomeric nucleosomal structure or the spacing of these structures. This study provides the first example of an essential centromeric protein gene variant in which subtle perturbation at the centromeric nucleosomal/chromatin level manifests in a significantly delayed lethality when compared with Cenpa null mice.
Kalitsis
Paul
P
Murdoch Childrenś Research Institute, Royal Children's Hospital, Flemington Road, Parkville 3052, Melbourne, Victoria, Australia.
Fowler
Kerry J
KJ
Earle
Elizabeth
E
Griffiths
Belinda
B
Howman
Emily
E
Newson
Ainsley J
AJ
Choo
K H Andy
KH
D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D001324:Autoantigens; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D020090:Chromosome Segregation / Q000235:genetics*; D003433:Crosses, Genetic; D017931:DNA Primers; D005455:Fluorescent Antibody Technique; D040461:Gene Components; D049452:Green Fluorescent Proteins; D006652:Histological Techniques; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice / Q000196:embryology* / Q000235:genetics*; D009707:Nucleosomes / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism
D001324:Autoantigens; C000619701:Cenpa protein, mouse; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D008164:Luminescent Proteins; D009707:Nucleosomes; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins