Neocentromere activity of structurally acentric mini-chromosomes in Drosophila.
Chromosome fragments that lack centromeric DNA (structurally acentric chromosomes) are usually not inherited in mitosis and meiosis. We previously described the isolation, after irradiation of a Drosophila melanogaster mini-chromosome, of structurally acentric mini-chromosomes that display efficient mitotic and meiotic transmission despite their small size (under 300 kb) and lack of centromeric DNA. Here we report that these acentric mini-chromosomes bind the centromere-specific protein ZW10 and associate with the spindle poles in anaphase. The sequences in these acentric mini-chromosomes were derived from the tip of the X chromosome, which does not display centromere activity or localize ZW10, even when separated from the rest of the X. We conclude that the normally non-centromeric DNAs present in these acentric mini-chromosomes have acquired centromere function, and suggest that this example of 'neocentromere' formation involves appropriation of a self-propagating centromeric chromatin structure. The potential relevance of these observations to the identity, propagation and function of normal centromeres is discussed.
Williams
B C
BC
Section of Genetics and Development, Cornell University, Ithaca, New York 14853, USA.
Murphy
T D
TD
Goldberg
M L
ML
Karpen
G H
GH
D000818:Animals; D018797:Cell Cycle Proteins; D002503:Centromere / Q000378:metabolism; D002875:Chromosomes; D004247:DNA / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D019476:Insect Proteins / Q000378:metabolism*; D011485:Protein Binding; D014960:X Chromosome
D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; C076055:Zw10 protein, Drosophila; D004247:DNA