Stable barley chromosomes without centromeric repeats.
The satellite sequences (AGGGAG)(n) and Ty3/gypsy-like retrotransposons are known to localize at the barley centromeres. Using a gametocidal system, which induces chromosomal mutations in barley chromosomes added to common wheat, we obtained an isochromosome for the short arm of barley chromosome 7H (7HS) that lacked the barley-specific satellite sequence (AGGGAG)(n). Two telocentric derivatives of the isochromosome arose in the progeny: 7HS* with and 7HS** without the pericentromeric C-band. FISH analysis demonstrated that both telosomes lacked not only the barley-specific centromeric (AGGGAG)(n) repeats and retroelements but also any of the known wheat centromeric tandem repeats, including the 192-bp, 250-bp, and TaiI sequences. Although they lacked these centromeric repeats, 7HS* and 7HS** both showed normal mitotic and meiotic transmission. Translocation of barley centromeric repeats to a wheat chromosome 4A did not generate a dicentric chromosome. Indirect immunostaining revealed that all tested centromere-specific proteins (rice CENH3, maize CENP-C, and putative barley homologues of the yeast kinetochore proteins CBF5 and SKP1) and histone H3 phosphorylated at serines 10 and 28 localized at the centromeric region of 7HS*. We conclude that the barley centromeric repeats are neither sufficient nor obligatory to assemble kinetochores, and we discuss the possible formation of a novel centromere in a barley chromosome.
Nasuda
S
S
Laboratory of Plant Genetics, Graduate School of Agriculture and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Hudakova
S
S
Schubert
I
I
Houben
A
A
Endo
T R
TR
D001399:Azure Stains; D002503:Centromere / Q000235:genetics* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D018014:Gene Transfer Techniques; D006657:Histones / Q000378:metabolism; D001467:Hordeum / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D018404:Isochromosomes / Q000235:genetics; D018386:Kinetochores / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D018626:Retroelements / Q000235:genetics*; D014908:Triticum / Q000235:genetics
D001399:Azure Stains; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D018626:Retroelements