The Role of the Kinetochore in Chromosome Organization

Lima-de-Faria, A.

doi:10.1111/j.1601-5223.1956.tb03013.x

Cited by 131 publications

(5 citation statements)

References 167 publications

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“…The metaphase chromosome is divided into two chromatids even within the centric constriction, a fact clearly demonstrated already by light microscopy (e.g. KOZLOV 1937; LIMADE-FARIA , 1955, 1956BAJER 1958; see also Fig. 4 and 5 of our present paper).…”

supporting

confidence: 83%

A fixation method for the observation of kinetochores

Clapham

Östergren

2009

Hereditas

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A fixation method using ethylene glycol, acetic acid and water, l:l:l, is described. It permits light microscope studies of the kinetochore, either in unstained material usmg phase contrast optics, or, after post-fixation with a chromic fixative, in permanent preparations stained with crystal violet. Haemanthus, Hyacinthus, SciNa, Tradescantia and Vicia were the test materials. Literature on centromere structure is briefly reviewed. Crystal violet demonstrates compact chromatin selectively and probably stains a complex of histones with chromium. The fixative has a swelling action on the chromosomes and extracts substance from them. The kinetochore is more resistant than the chromosome body to this treatment. This resistance is due to a f m r bonding between the constituent components of the kinetochore. a firmness developed from the evolutionary adaptation of the kinetochore to resist damage by the pulling action of the spindle. The achromatic character of the kinetochore after some fixation methods may be due to the compactness of its structure which prevents penetration of dye molecules. After our fixation the kinetochore can be stained by crystal violet and the Feulgen reaction. The same compactness might also explain the differential staining of kinetochores by mitochondrial techniques. Lena Clapham, Department of Genetics and Plant Breeding. P.O.B. 7003, S-7-50 07 Uppsala 7 , SwedenThe introduction of the band-staining techniques with fluorochromes by CASPERSSON et al. (1968) and with Giemsa by PARDUE and GALL (1970) opened a new era in chromosome cytology. Much attention was now focused on the possibility of staining chromosome regions differentially, and many technical modifications and new related methods were developed for this purpose.However, there also exist some earlier studies on differential staining of special regions in metaphase and anaphase chromosomes. One region that, on several occasions, had been subjected to differential staining is the kinetochore, the minute body or granule to which the traction fibres of the spindle are attached. These observations are reviewed by GEITLW (1938), LEVAN (1946), Scm-DER (1953) and LWKX (1970). There are also some early studies in which heterochromatic regions could be demonstrated in the chromosomes during their contraction phases, for instance LEVAN (1946). The present paper is devoted to a more detailed description of some investigations on a method developed by ~STERGREN (1947) for the differential staining of kinetochores. The cells were fixed in a 1:l:l mixture of water, acetic acid and ethylene glycol or glycerol. This was followed by a postfixation in chrome-acetic formalin and staining with crystal violet. The paper by OSTERGREN and h m s m (1973) is a preliminary report by the present writers on the results described here. A fixation in this acetic glycol mixture also permits an observation of kinetochores in unstained chromosomes by means of phase contrast microscopy (OSTERGREN and ANDERSSON 1973). A phase contrast study on the kinetochores...

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supporting

confidence: 83%

A fixation method for the observation of kinetochores

Clapham

Östergren

2009

Hereditas

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“…This is the case in the chromomere gradients of rye (LIMA-DE-FARIA 1952) in the distal heterochromatic segments of Cyclops (BEERMANN 1977) andin Hepatica (MARKS andSCHWEIZER 1974). There is not only order but also hierarchy within the chromosome (LIMA-DE-FARIA 1956).…”

Section: Structural and Experimental Evidence On The Chromosome Fieldmentioning

confidence: 98%

Classification of genes, rearrangements and chromosomes according to the chromosome field

Lima-de-Faria

2009

Hereditas

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The study of over 700 species, from algae to humans, reveals that specific DNA sequences, have an optimal territory within the centromere‐telomere field. These DNA sequences have maintained their territory within the chromosome field for millions of years irrespective of variation in arm length, of change in chromosome type and of species evolution. Some of these DNA sequences have been isolated biochemically or analysed at the molecular level. They include, e.g., the proximal heterochromatic segments, the genes for ribosomal RNA, and the telomeric heterochromatin. Order prevails in the eukaryotic chromosome. This order allows classification of genes, rearrangements and chromosomes on a genetic basis. Genes are classified as centrons, medons and telons. Rearrangements are classified as: conservative, discordant, disruptive, destructive and incompatible. Chromosomes are also classified depending on their length, arm size and number. These chromosome properties and features now acquire an organizatory meaning which they lacked previously. The available molecular information supports the evidence from the field. The study of the split gene reveals that it is the relative position of the DNA sequences which determines their function. On the basis of the chromosome field, predictions can be made concerning gene organization, gene function and chromosome evolution.

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“…Instead the centromere would seem to be still functionally single. If it is double or quadruple, as had been observed in root tip chromosomes (~S T E R G R E N , 1947: TJIO andLEVAN, 1950) and also at meiosis (LIMA-DE-FARIA, 1956), the parts are held together. ANDERssoN (1947) describes such a misdivision in which the centromere components themselves are attracted to each pole resulting in a stretching of the centromere region.…”

Section: Behaviour Of Univalentsmentioning

confidence: 83%