Centromere Function and Nondisjunction Are Independent Components of the Maize B Chromosome Accumulation Mechanism

Han, Fangpu; Lamb, Jonathan C.; Yu, Weichang; Gao, Zhi; Birchler, James A.

doi:10.1105/tpc.106.049577

Cited by 56 publications

(56 citation statements)

References 33 publications

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“…The adhesion sites appear to be in the pericentromeric regions (Fig. 1F), and are probably independent of the centromeric function, as demonstrated for the maize B chromosome (Han et al, 2007). The presence of such elements that react with the B centromere is also inferred from the fact that the nondisjunction frequency of the standard B s chromosomes was decreased significantly when it coexists with B s -1 (Table 2).…”

Section: Nondisjunctionmentioning

confidence: 76%

Dissection of rye B chromosomes, and nondisjunction properties of the dissected segments in a common wheat background

et al. 2008

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The rye B chromosome is a supernumerary chromosome that increases in number in its host by directed postmeiotic drive. Two types of rye B chromosomes that had been introduced into common wheat were dissected into separate segments by the gametocidal system to produce a number of rearranged B chromosomes, such as telosomes, terminal deletions and translocations with wheat chromosomes. A total of 13 dissected B chromosomes were isolated in common wheat, and were investigated for their nondisjunction properties. Rearranged B chromosomes, separated from their B-specific repetitive sequences on the distal part of the long arm, did not undergo nondisjunction, and neither did a translocated wheat chromosome carrying a long-arm distal segment containing the Bspecific repetitive sequences. However, such rearranged B chromosomes, missing their B-specific sequences could undergo nondisjunction when they coexisted with the standard B chromosome or a wheat chromosome carrying the B-specific sequences. Deficiencies of the short arm did not completely abolish the nondisjunction properties of the B chromosome, but did reduce the frequency of nondisjunction. These results confirmed previous suggestions that the directed nondisjunction of the rye B chromosome is controlled by two elements, pericentromeric sticking sites and a trans-acting element carried at the distal region of the long arm of the B chromosome. Additionally, it is now shown that the distal region of the long arm of the B chromosome which provides this function is that which carries the B-specific repetitive sequences.

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Section: Nondisjunctionmentioning

confidence: 76%

Dissection of rye B chromosomes, and nondisjunction properties of the dissected segments in a common wheat background

et al. 2008

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“…However, this region does not control the differential grouping of centromeres of A chromosomes in generative and vegetative nuclei. Han et al, 2007). As the Bs of rye and maize originated independently, comparable drive mechanisms in both species evolved in parallel.…”

Section: The Drive Mechanism Of the B Chromosome Of Rye: A Modelmentioning

confidence: 99%

Nondisjunction in Favor of a Chromosome: The Mechanism of Rye B Chromosome Drive during Pollen Mitosis

et al. 2012

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B chromosomes (Bs) are supernumerary components of the genome and do not confer any advantages on the organisms that harbor them. The maintenance of Bs in natural populations is possible by their transmission at higher than Mendelian frequencies. Although drive is the key for understanding B chromosomes, the mechanism is largely unknown. We provide direct insights into the cellular mechanism of B chromosome drive in the male gametophyte of rye (Secale cereale). We found that nondisjunction of Bs is accompanied by centromere activity and is likely caused by extended cohesion of the B sister chromatids. The B centromere originated from an A centromere, which accumulated B-specific repeats and rearrangements. Because of unequal spindle formation at the first pollen mitosis, nondisjoined B chromatids preferentially become located toward the generative pole. The failure to resolve pericentromeric cohesion is under the control of the B-specific nondisjunction control region. Hence, a combination of nondisjunction and unequal spindle formation at first pollen mitosis results in the accumulation of Bs in the generative nucleus and therefore ensures their transmission at a higher than expected rate to the next generation.

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“…Chromosomal rearrangement, or de novo centromere formation, can produce a chromosome containing two centromeric regions. To be stably inherited, one centromere of the dicentric chromosome must be inactivated, as a chromosome with two functional centromeres will suffer chromosomal breakage (Han et al, 2006(Han et al, , 2007Zhang et al, 2010;Gao et al, 2011). If both centromeres remain active and the chromosome pulls apart, the broken ends of the chromosome will subsequently fuse and undergo the breakage-fusion-bridge (BFB) cycle to form a new dicentric chromosome (McClintock, 1939(McClintock, , 1941.…”

Section: Introductionmentioning

confidence: 99%

Formation of a Functional Maize Centromere after Loss of Centromeric Sequences and Gain of Ectopic Sequences

Zhang

Pang

et al. 2013

The Plant Cell

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The maize (Zea mays) B centromere is composed of B centromere-specific repeats (ZmBs), centromere-specific satellite repeats (CentC), and centromeric retrotransposons of maize (CRM). Here we describe a newly formed B centromere in maize, which has lost CentC sequences and has dramatically reduced CRM and ZmBs sequences, but still retains the molecular features of functional centromeres, such as CENH3, H2A phosphorylation at Thr-133, H3 phosphorylation at Ser-10, and Thr-3 immunostaining signals. This new centromere is stable and can be transmitted to offspring through meiosis. Anti-CENH3 chromatin immunoprecipitation sequencing revealed that a 723-kb region from the short arm of chromosome 9 (9S) was involved in the formation of the new centromere. The 723-kb region, which is gene poor and enriched for transposons, contains two abundant DNA motifs. Genes in the new centromere region are still transcribed. The original 723-kb region showed a higher DNA methylation level compared with native centromeres but was not significantly changed when it was involved in new centromere formation. Our results indicate that functional centromeres may be formed without the known centromere-specific sequences, yet the maintenance of a high DNA methylation level seems to be crucial for the proper function of a new centromere.

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Centromere Function and Nondisjunction Are Independent Components of the Maize B Chromosome Accumulation Mechanism

Cited by 56 publications

References 33 publications

Dissection of rye B chromosomes, and nondisjunction properties of the dissected segments in a common wheat background

Dissection of rye B chromosomes, and nondisjunction properties of the dissected segments in a common wheat background

Nondisjunction in Favor of a Chromosome: The Mechanism of Rye B Chromosome Drive during Pollen Mitosis

Formation of a Functional Maize Centromere after Loss of Centromeric Sequences and Gain of Ectopic Sequences

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