Abstract
Neocentromere activity is a classic example of nonkinetochore chromosome movement. In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase. Here we describe experiments that test how neocentromere activity affects the function of linked centromere/kinetochores (kinetochores) and whether neocentromeres and kinetochores are mobilized on the spindle by the same mechanism. Using a newly developed system for observing meiotic chromosome congression and segregation in living maize cells, we show that neocentromeres are active from prometaphase through anaphase. During mid-anaphase, normal chromosomes move on the spindle at an average rate of 0.79 micron/min. The presence of Ab10 does not affect the rate of normal chromosome movement but propels neocentromeres poleward at rates as high as 1.4 micron/min. Kinetochore-mediated chromosome movement is only marginally affected by the activity of a linked neocentromere. Combined in situ hybridization/immunocytochemistry is used to demonstrate that unlike kinetochores, neocentromeres associate laterally with microtubules and that neocentromere movement is correlated with knob size. These data suggest that microtubule depolymerization is not required for neocentromere motility. We argue that neocentromeres are mobilized on microtubules by the activity of minus end-directed motor proteins that interact either directly or indirectly with knob DNA sequences.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
Neocentromeres are active from prometaphase through anaphase in maize meiosis.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e1“we show that neocentromeres are active from prometaphase through anaphase”
Claim · model-written summary
Normal chromosomes move on the spindle at an average rate of 0.79 micron/min during mid-anaphase.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e2“During mid-anaphase, normal chromosomes move on the spindle at an average rate of 0.79 micron/min”
Claim · model-written summary
The presence of Ab10 does not affect the rate of normal chromosome movement.
- Treatment
- The presence of Ab10e3
- Gene
- Ab10e3
- Outcome
- rate of normal chromosome movemente3
- Direction
- does not affecte3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e3“The presence of Ab10 does not affect the rate of normal chromosome movement but propels neocentromeres poleward at rates as high as 1.4 micron/min”
Claim · model-written summary
Ab10 propels neocentromeres poleward at rates as high as 1.4 micron/min.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e3“The presence of Ab10 does not affect the rate of normal chromosome movement but propels neocentromeres poleward at rates as high as 1.4 micron/min”
Claim · model-written summary
Kinetochore-mediated chromosome movement is only marginally affected by a linked neocentromere.
- Treatment
- the activity of a linked neocentromeree4
- Outcome
- Kinetochore-mediated chromosome movemente4
- Direction
- only marginally affectede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e4“Kinetochore-mediated chromosome movement is only marginally affected by the activity of a linked neocentromere”
Claim · model-written summary
Unlike kinetochores, neocentromeres associate laterally with microtubules.
- Outcome
- neocentromeres associate laterally with microtubulese5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e5“unlike kinetochores, neocentromeres associate laterally with microtubules and that neocentromere movement is correlated with knob size”
Claim · model-written summary
Neocentromere movement is correlated with knob size.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e5“unlike kinetochores, neocentromeres associate laterally with microtubules and that neocentromere movement is correlated with knob size”
Claim · model-written summary
Microtubule depolymerization is not required for neocentromere motility.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e6“These data suggest that microtubule depolymerization is not required for neocentromere motility”
Claim · model-written summary
Neocentromeres are mobilized on microtubules by minus end-directed motor proteins.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In maize, neocentromeres are induced by a gene or genes on Abnormal chromosome 10 (Ab10) which causes heterochromatic knobs to move poleward at meiotic anaphase”
e7“We argue that neocentromeres are mobilized on microtubules by the activity of minus end-directed motor proteins”