Spindle sensitivity to isopropyl-N-phenyl-carbamate and griseofulvin of common wheat plants carrying different doses of the Ph1 gene

1984 ◽  
Vol 26 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Giampiero Gualandi ◽  
Carla Ceoloni ◽  
Moshe Feldman ◽  
Lydia Avivi

Lines of common wheat cv. 'Chinese Spring' carrying different doses of the Ph1 gene, located on the long arm of chromosome 5B were treated with the antimitotic agents griseofulvin and isopropyl-N-phenyl-carbamate (IPC). Treatments with low griseofulvin concentrations and IPC resulted mainly in the production of a high percentage of cells exhibiting spindle disorganization at metaphase and multipolar cells at anaphase–telophase. These treatments did not differentially affect the tested genotypes. On the other hand, higher griseofulvin concentrations induced the appearance of frequent C-metaphases and C-anaphases because of complete disruption of the spindle microtubules; in such cases, more pronounced sensitivity was observed in a line lacking the Ph1 gene than in lines disomic and tetrasomic for chromosome 5B. From this evidence it can be concluded that subcellular structures regulating microtubule organization and orientation, which are apparently the target of IPC and low griseofulvin concentrations, are not related to the action of the Ph1 gene. Rather, tubulin–microtubules equilibrium, which is affected by colchicine and high griseofulvin concentrations, is influenced by the action of this gene. Thus, the Ph1 gene product may correspond to a tubulin or a microtubule-associated protein which in turn stabilizes microtubule structure. In either case, the equilibrium tubulin–microtubules would be shifted towards microtubules in plants containing two doses of Ph1 and even more in plants containing an extra dose of this gene.Key words: spindle, Triticum, microtubules, antitubulins, griseofulvin.


1984 ◽  
Vol 26 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Carla Ceoloni ◽  
Lydia Avivi ◽  
Moshe Feldman

Mitotic spindle sensitivity to colchicine of a common wheat line carrying a mutation at the Ph1 locus which increases homoeologous pairing at meiosis, was studied in treated root-tip cells and compared with that of wild type (Ph1/Ph1) and plants deficient for chromosome 5B. Spindle sensitivity was determined by the percentage of fully affected cells of the overall metaphase cell population. The high-pairing mutant (ph1b/ph1b), which is assumed to be a deficiency for the Ph1 locus on the long arm of chromosome 5B, was found to be significantly more sensitive to colchicine than the corresponding control line, i.e., plants carrying the wild-type allele, Ph1. The sensitivity of the mutant was similar to that of plants deficient for chromosome 5B. It thus becomes highly probable that spindle sensitivity to colchicine, previously found in plants carrying different doses of chromosomal arm 5BL, is indeed determined by the Ph1 gene. This gene presumably exerts its effect on the spindle via modification of some microtubular components. Thus, microtubules are suggested to be a possible target structure for this gene, which is known to affect chromosomal distribution and degree of homologous and homoeologous association in somatic and premeiotic cells, as well as the pattern of meiotic pairing.Key words: spindle, Triticum, microtubules, colchicine.



1976 ◽  
Vol 18 (2) ◽  
pp. 255-261
Author(s):  
Shoji Shigenaga

Two kinds of sextuple monosomics for A-genome chromosomes, namely, one plant simultaneously deficient for chromosomes 1A, 2A, 4A, 5A, 6A and 7A and the other deficient for 1A, 2A, 3A, 4A, 5A and 6A, were produced in a systematic way in the variety Chinese Spring. Sextuple monosomics (15″ + 6′) were selected in the progenies of crosses between quintuple monosomics (16″ + 5′) and nullisomics (20″) which lacked the sixth pair of chromosomes. The sextuple monosomics were smaller, with reduced vigor and later maturity, compared with normal plants. They showed stable chromosome behavior in meiosis and retained fertility in both sexes. Female gametes with n = 16, 17, 18, 19, 20 or 21 produced from the quintuple monosomics functioned well in fertilization.



1986 ◽  
Vol 28 (2) ◽  
pp. 240-246 ◽  
Author(s):  
C. Ceoloni ◽  
I. Strauss ◽  
M. Feldman

While an extra dose of chromosome 2A of common wheat, previously reported to carry a pairing promoter on its short arm, did not increase pairing between homoeologous chromosomes in F1 hybrids between common wheat cv. Chinese Spring (CS) and Aegilops variabilis, two doses of chromosome 2D or 2B caused a significant increase in homoeologous pairing. Evidently, chromosomes 2D and 2B carry a pairing promoter(s). Studies of F1 hybrids between aneuploids of CS, either deficient for chromosome 2D or having it in an extra dose, and Ae. variabilis, Ae. longissima, and Secale cereale supported the finding that this chromosome carries a pairing promoter. Using ditelosomic lines, the promoter was found to be located on the short arm of 2D (2DS). It was deduced that the promoter of 2B is also located on the homoeologous short arm, i.e., on 2BS. Evidence was obtained that the long arm of 2D may carry a suppressor(s) of pairing. Thus, the short arm of 2A, 2D, and 2B carries a pairing promoter(s), while the long arm of 2D and possibly of 2A and 2B carry a minor suppressor(s). The promoters are more potent than the suppressors and the overall effect of group-2 chromosomes is pairing promotion.Key words: wheat, homoeologous pairing, pairing promoter, pairing suppressor, intergeneric hybrid, meiosis.



1975 ◽  
Vol 53 (20) ◽  
pp. 2336-2344 ◽  
Author(s):  
K. Kobrehel ◽  
P. Feillet

Polyacrylamide-slab gel electrophoresis of peroxidases of different Triticum and Aegilops species and of nullisomic–tetrasomic lines of Chinese spring wheat showed that T. aestivum chromosomes 7D, 4B, and 7A are the carriers of genes coding the synthesis of peroxidase a, peroxidase c, and peroxidase d, respectively. The indirect effect of modified chromosome systems and a special effect of chromosome 5B on peroxidase synthesis have also been observed. The chromosomal and genomic origin of the three other peroxidases (b, e, and f) detected in common wheat could not be definitively established.



Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 974-977 ◽  
Author(s):  
A. Charpentier ◽  
M. Feldman ◽  
Y. Cauderon

Chromosome pairing at first meiotic metaphase was studied in F1 hybrids between tetraploid cytotypes of Agropyron elongatum and common wheat lines of the cultivar Chinese Spring, carrying zero, one, and two doses of Ph1. The bivalentization gene system of A. elongatum could not compensate for the absence of Ph1: hybrids deficient for this gene exhibited pairing between the Agropyron E1 and E2 chromosomes, between the wheat A, B, and D chromosomes, and between the Agropyron and the wheat chromosomes. In hybrids with one or two doses of Ph1, pairing was restricted to the Agropyron E1 and E2 chromosomes. It was concluded that E1 and E2 are distant homologues, thus further supporting the autoploidy nature of tetraploid A. elongatum. The genomic relationships in other polyploid species of the genus Agropyron is discussed in the light of this evidence.Key words: chromosome pairing, Triticum, common wheat, Agropyron.



Genetics ◽  
1998 ◽  
Vol 150 (3) ◽  
pp. 1199-1208 ◽  
Author(s):  
Juan M Vega ◽  
Moshe Feldman

Abstract The analysis of the pattern of isochromosome pairing allows one to distinguish factors affecting presynaptic alignment of homologous chromosomes from those affecting synapsis and crossing-over. Because the two homologous arms in an isochromosome are invariably associated by a common centromere, the suppression of pairing between these arms (intrachromosome pairing) would indicate that synaptic or postsynaptic events were impaired. In contrast, the suppression of pairing between an isochromosome and its homologous chromosome (interchromosome pairing), without affecting intrachromosome pairing, would suggest that homologous presynaptic alignment was impaired. We used such an isochromosome system to determine which of the processes associated with chromosome pairing was affected by the Ph1 gene of common wheat—the main gene that restricts pairing to homologues. Ph1 reduced the frequency of interchromosome pairing without affecting intrachromosome pairing. In contrast, intrachromosome pairing was strongly reduced in the absence of the synaptic gene Syn-B1. Premeiotic colchicine treatment, which drastically decreased pairing of conventional chromosomes, reduced interchromosome but not intrachromosome pairing. The results support the hypothesis that premeiotic alignment is a necessary stage for the regularity of meiotic pairing and that Ph1 relaxes this alignment. We suggest that Ph1 acts on premeiotic alignment of homologues and homeologues as a means of ensuring diploid-like meiotic behavior in polyploid wheat.



Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Ernest D. P. Whelan ◽  
G. B. Schaalje

Aneuploid seedlings of the common wheat (Triticum aestivum L.) cv. Chinese Spring (CS) that are nullisomic or telosomic for the long arm of chromosome 6D are susceptible to chilling injury under prolonged exposure to 6 °C; normal euploids or telosomics for the short arm are not. Studies of seedling grown for various durations at 20 °C prior to growth at 6 °C showed that chilling injury was a juvenile phenomenon and that the extent of injury was inversely proportional to the duration of growth at 20 °C to a maximum of about 14 days. When reciprocal crosses were made between susceptible 6D nullisomics or long-arm ditelocentrics of CS and resistant 6D nullisomics of three spring and one winter wheat cultivars, progenies from aneuploid F1 hybrids all segregated for susceptibility as a recessive trait and at a frequency approximating a dihybrid ratio; no cytoplasmic effects were detected. Aneuploids of the group 6 homoeologues of the spring wheat cvs. Cadet and Rescue were resistant, as were group 6 whole-chromosome substitutions of eight different donor wheats in the recipient parent CS and 56 other euploids tested. Genes for resistance to chilling injury appear to involve the group 6 chromosomes and the short arm of 6D in Chinese Spring. In contrast with chilling injury, all aneuploid lines with only four doses of the "corroded" loci on group 6 chromosomes exhibited chlorotic symptoms.Key words: Triticum aestivum, chilling injury.



2002 ◽  
Vol 156 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Toshiro Ohta ◽  
Russell Essner ◽  
Jung-Hwa Ryu ◽  
Robert E. Palazzo ◽  
Yumi Uetake ◽  
...  

By using monoclonal antibodies raised against isolated clam centrosomes, we have identified a novel 135-kD centrosomal protein (Cep135), present in a wide range of organisms. Cep135 is located at the centrosome throughout the cell cycle, and localization is independent of the microtubule network. It distributes throughout the centrosomal area in association with the electron-dense material surrounding centrioles. Sequence analysis of cDNA isolated from CHO cells predicted a protein of 1,145–amino acid residues with extensive α-helical domains. Expression of a series of deletion constructs revealed the presence of three independent centrosome-targeting domains. Overexpression of Cep135 resulted in the accumulation of unique whorl-like particles in both the centrosome and the cytoplasm. Although their size, shape, and number varied according to the level of protein expression, these whorls were composed of parallel dense lines arranged in a 6-nm space. Altered levels of Cep135 by protein overexpression and/or suppression of endogenous Cep135 by RNA interference caused disorganization of interphase and mitotic spindle microtubules. Thus, Cep135 may play an important role in the centrosomal function of organizing microtubules in mammalian cells.



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