Effect of Ph2 mutants promoting homoeologous pairing on spindle sensitivity to colchicine in common wheat

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 658-663
Author(s):  
Carla Ceoloni ◽  
Moshe Feldman
Keyword(s):  
Common Wheat ◽  
Suppressor Gene ◽  
Intergeneric Hybrids ◽  
Differential Sensitivity ◽  
Root Tip ◽  
Lower Sensitivity ◽  
Homoeologous Pairing ◽  
Wild Type ◽  
Cellular Target ◽  
Chromosome Arm

Two lines of common wheat cv. Chinese Spring carrying mutant alleles for the Ph2 homoeologous pairing-suppressor gene on chromosome arm 3DS promoting homoeologous pairing in wheat interspecific and intergeneric hybrids have been tested for their mitotic sensitivity to colchicine. Both the ph2a mutation, which corresponds to a fairly long deletion of 3DS, and ph2b, which is either an intragenic change or a very small deletion, as well as the ph2a/ph2b heteroallelic combination and the deficiency for the entire 3DS arm (ditelo 3DL), conditioned a significantly lower sensitivity to colchicine than that determined by the wild-type allele Ph2 (euploid and ditelo 3DS). Observation of both metaphase and anaphse root-tip cell populations, treated with various colchicine concentrations, provided similar results. The degree of spindle disruption in 2 × 10−4 M colchicine, as measured by the percentage of fully affected metaphases (C type), was significantly reduced in ph2 and Ph2− genotypes and, consequently, a larger proportion of cells could proceed toward anaphase and also had a regular segregation pattern at this stage. The differential sensitivity of ph2 genotypes to colchicine is in the opposite direction to that previously found for ph1 genotypes, lacking the homoeologous pairing suppressor on chromosome arm 5BL. The ph2 mutation, while promoting homoeologous pairing as ph1 does, decreases spindle sensitivity to colchicine with respect to the wild-type (ph2) allele rather than increasing it, as ph1 does. The observed alteration of spindle sensitivity to colchicine that mutants for structurally unrelated but functionally related genes (Ph1 and Ph2) condition is interpreted as a highly probable coincidence in their cellular target. It is assumed therefore that these loci affect the equilibrium between tubulin and microtubules. Through this effect they presumably determine chromosome positioning in somatic and premeiotic stages, leading to different pairing patterns at meiosis. Key words: Triticum aestivum, tubulin, pairing suppressors, somatic association.

Spindle sensitivity to colchicine of the Ph1 mutant in common wheat

1984 ◽  
Vol 26 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Carla Ceoloni ◽  
Lydia Avivi ◽  
Moshe Feldman
Keyword(s):  
Common Wheat ◽  
Root Tip ◽  
Control Line ◽  
Wild Type ◽  
Chromosomal Distribution ◽  
Chromosome 5B ◽  
Ph1 Locus ◽  
Ph1 Gene ◽  
Tip Cells ◽  
Different Doses

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.

Combining mutations for the two homoeologous pairing suppressor genes Ph1 and Ph2 in common wheat and in hybrids with alien Triticeae

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 377-386 ◽  
Author(s):  
Carla Ceoloni ◽  
Paolo Donini
Keyword(s):  
Common Wheat ◽  
Interspecific Hybrids ◽  
Double Mutant ◽  
Homoeologous Pairing ◽  
Suppressor Genes ◽  
Plant Variation ◽  
Significant Difference ◽  
Chromosome Arm ◽  
Aegilops Variabilis ◽  
Pairing Behaviour

Two lines of common wheat cv. Chinese Spring, carrying simultaneous mutations for the two major homoeologous pairing wheat suppressor genes Ph1 and Ph2 have been developed and their pairing behaviour compared with that of the ph1b mutant of the same cultivar. Besides carrying the ph1b mutation, the first double mutant line lacked the chromosome arm pair 3DS, containing Ph2, whereas the second had a euploid constitution and carried the ph1b allele on 3DS. Hybrids of Aegilops variabilis and Secale cereale with mono-5B (ph1b) and 3D/3DL plants have also been obtained, where the 3D versus 3DL presence marked the two pairing alternatives (ph1b only and ph1b + Ph2−, respectively). In the wheat × Ae. variabilis hybrids, an 8% increase in total chromosome pairing, almost entirely ascribable to an increment of multivalent associations, was observed in the 2n = 34 + t plants with respect to their 2n = 35 sibs. The number of bivalents showed no significant difference, but a tendency towards a decrease, which was significant for the rod types, was exhibited by the Ph2− plants. A weaker but similar effect was observed in wheat itself. The different mutants, in fact, showed a similar percentage of paired chromosomes but varied in their pairing pattern. A significant reduction in the number of bivalents, owing to a decrease of the rings, only partly compensated for by an increase of the rods, was observed in the double mutants. They also exhibited an increase in the multivalent fraction, which was significant for the most complex associations. In both common wheat and its hybrids with Ae. variabilis the addition of a ph2 mutation thus seems to reinforce the ph1b effect in promoting homoeologous pairing. On the other hand, such an effect was not noticed in the wheat × S. cereale hybrids. However, possible quantitative differences could have been masked by the considerable plant-to-plant variation and potential differences in relative incidence of wheat–wheat versus wheat–rye associations were undetectable in the Feulgen-stained materials analyzed.Key words: common wheat, interspecific hybrids, homoeologous pairing, Ph mutations.

scholarly journals THE MECHANISM OF SOMATIC ASSOCIATION IN COMMON WHEAT, TRITICUM AESTIVUM L. IV. FURTHER EVIDENCE FOR MODIFICATION OF SPINDLE TUBULIN THROUGH THE SOMATIC-ASSOCIATION GENES AS MEASURED BY VINBLASTINE BINDING

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 379-385
Author(s):  
Lydia Avivi ◽  
Moshe Feldman
Keyword(s):  
Triticum Aestivum ◽  
Genetic Control ◽  
Common Wheat ◽  
Triticum Aestivum L ◽  
Suppressor Gene ◽  
Single Site ◽  
Root Tip ◽  
Binding Ability ◽  
Tip Cells ◽  
Root Tip Cells

ABSTRACT Treatment with the antitubulin vinblastine was found to disrupt the spindle system in dividing root-tip cells of common wheat, Triticum aestivum L. Genotypes lacking the somatic association suppressor gene on 5BL, or containing the somatic-association promoter on 5BS, were found to be more sensitive to the treatment. In genetic lines carrying the somatic association suppressor, sensitivity to vinblastine was lower and there was a direct correlation between dosage of the suppressor gene (0, 2, and 4) and the decrease in spindle disruption on exposure to various concentrations of vinblastine. It is concluded that the somatic association genes affect binding ability of spindle tubulin to vinblastine. Since the same genes affect binding of colchicine to tubulin and since the two alkaloids attach to different sites it is assumed that the somatic association suppressor gene has a broad effect on the tubulin molecules which is not confined to a single site. The relevance of genetic control of antitubulin binding to somatic association is discussed.

Arm homoeology of wheat and rye chromosomes

Genome ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 873-882 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
P. G. Goicoechea ◽  
R. Giraldez
Keyword(s):  
Key Words ◽  
Common Wheat ◽  
Chinese Spring ◽  
Structural Changes ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Wheat Evolution ◽  
C Banding ◽  
Chromosome Arm ◽  
Homoeology Relationships

Meiotic pairing was studied at metaphase I in three different cv. Chinese Spring × rye hybrid combinations (5B deficient, 3D deficient, and normal ABDR) to establish the arm homoeology of wheat and rye chromosomes. The majority of individual wheat chromosomes and their arms, as well as the arms of chromosomes 1R and 5R, were identified by means of C-banding. The results on pairing relationships support the genome reallocation of chromosomes 4A and 4B. The short arms of wheat chromosomes belonging to homoeologous groups 1, 3, 5, and 6 and of chromosome pairs 4A–4D and 7A–7D showed full pairing homoeology as well as the long arms of wheat chromosomes of groups 1, 3, 6, and 7 and of chromosome pairs 4A–4D and 5B–5D. Chromosomes 2A, 2B, and 2D were homoeologous, but the homoeologies of their arms were not identified. Reduced homoeologies of the 4BL arm to 7AS and 7DS, of the 5AL arm to 4AL and 4DL, and of the 7BS arm to 5BL and 5DL were identified. Arms 4BL, 5AL, and 7BS are involved in a double translocation that arose during the evolution of common wheat. The homoeology relationships of chromosome arm 4BS were not identified since this arm seldom paired. The homoeologous pairing pattern between wheat chromosomes was characterized by a remarkable predominance of A–D associations, altered only by structural changes in groups 4 and 5. Chromosome arm 1RL showed full pairing homoeology to 1AL, 1BL, and 1DL, while 5RL was homoeologous to 5AL and partially homoeologous to 4AL and 4DL. It is concluded that 5RL carries a translocated segment from 4RL. Key words: homoeologous pairing, translocations, wheat evolution, C-banding.

scholarly journals Antitumor Effects of PRIMA-1 and PRIMA-1Met (APR246) in Hematological Malignancies: Still a Mutant P53-Dependent Affair?

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 98
Author(s):  
Paola Menichini ◽  
Paola Monti ◽  
Andrea Speciale ◽  
Giovanna Cutrona ◽  
Serena Matis ◽  
...  
Keyword(s):  
Hematological Malignancies ◽  
Cell Metabolism ◽  
Therapy Response ◽  
Tp53 Gene ◽  
Suppressor Gene ◽  
Lower Percentage ◽  
Mutant P53 ◽  
Wild Type ◽  
Antitumor Effects ◽  
Tp53 Tumor Suppressor Gene

Because of its role in the regulation of the cell cycle, DNA damage response, apoptosis, DNA repair, cell migration, autophagy, and cell metabolism, the TP53 tumor suppressor gene is a key player for cellular homeostasis. TP53 gene is mutated in more than 50% of human cancers, although its overall dysfunction may be even more frequent. TP53 mutations are detected in a lower percentage of hematological malignancies compared to solid tumors, but their frequency generally increases with disease progression, generating adverse effects such as resistance to chemotherapy. Due to the crucial role of P53 in therapy response, several molecules have been developed to re-establish the wild-type P53 function to mutant P53. PRIMA-1 and its methylated form PRIMA-1Met (also named APR246) are capable of restoring the wild-type conformation to mutant P53 and inducing apoptosis in cancer cells; however, they also possess mutant P53-independent properties. This review presents the activities of PRIMA-1 and PRIMA-1Met/APR246 and describes their potential use in hematological malignancies.

scholarly journals Dysfunction of the TP53 tumor suppressor gene in lymphoid malignancies

Blood ◽  
2012 ◽  
Vol 119 (16) ◽  
pp. 3668-3683 ◽  
Author(s):  
Zijun Y. Xu-Monette ◽  
L. Jeffrey Medeiros ◽  
Yong Li ◽  
Robert Z. Orlowski ◽  
Michael Andreeff ◽  
...  
Keyword(s):  
Tp53 Gene ◽  
Suppressor Gene ◽  
Wild Type ◽  
Lymphoid Malignancies ◽  
The Status ◽  
Tp53 Tumor Suppressor Gene ◽  
P53 Activation ◽  
Apoptotic Pathways ◽  
P53 Inactivation ◽  
Tp53 Pathway

AbstractMutations of the TP53 gene and dysregulation of the TP53 pathway are important in the pathogenesis of many human cancers, including lymphomas. Tumor suppression by p53 occurs via both transcription-dependent activities in the nucleus by which p53 regulates transcription of genes involved in cell cycle, DNA repair, apoptosis, signaling, transcription, and metabolism; and transcription-independent activities that induces apoptosis and autophagy in the cytoplasm. In lymphoid malignancies, the frequency of TP53 deletions and mutations is lower than in other types of cancer. Nonetheless, the status of TP53 is an independent prognostic factor in most lymphoma types. Dysfunction of TP53 with wild-type coding sequence can result from deregulated gene expression, stability, and activity of p53. To overcome TP53 pathway inactivation, therapeutic delivery of wild-type p53, activation of mutant p53, inhibition of MDM2-mediated degradation of p53, and activation of p53-dependent and -independent apoptotic pathways have been explored experimentally and in clinical trials. We review the mechanisms of TP53 dysfunction, recent advances implicated in lymphomagenesis, and therapeutic approaches to overcoming p53 inactivation.

scholarly journals Wilms' Tumor Gene (WT1) Competes With Differentiation-Inducing Signal in Hematopoietic Progenitor Cells

Blood ◽  
1998 ◽  
Vol 91 (8) ◽  
pp. 2969-2976 ◽  
Author(s):  
Kazushi Inoue ◽  
Hiroya Tamaki ◽  
Hiroyasu Ogawa ◽  
Yoshihiro Oka ◽  
Toshihiro Soma ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tumor Suppressor ◽  
Progenitor Cells ◽  
Wilms Tumor ◽  
Suppressor Gene ◽  
Hematopoietic Progenitor Cells ◽  
Wt1 Gene ◽  
Wild Type ◽  
Hematopoietic Progenitor ◽  
Oncogenic Function

The WT1 gene is a tumor-suppressor gene that was isolated as a gene responsible for Wilms' tumor, a childhood kidney neoplasm. We have previously reported that the WT1 gene is strongly expressed in leukemia cells with an increase in its expression levels at relapse and an inverse correlation between its expression levels and prognosis, thus making it a novel tumor marker for leukemic blast cells. Furthermore, WT1 antisense oligomers have been found to inhibit the growth of leukemic cells. These results strongly suggested the involvement of the WT1 gene in human leukemogenesis. The present study was performed to prove our hypothesis that the WT1 gene plays a key role in leukemogenesis and performs an oncogenic function in hematopoietic progenitor cells, rather than a tumor-suppressor gene function. 32D cl3, an interleukin-3–dependent myeloid progenitor cell line, differentiates into mature neutrophils in response to granulocyte colony-stimulating factor (G-CSF). However, when transfected wild-type WT1 gene was constitutively expressed in 32D cl3, the cells stopped differentiating and continued to proliferate in response to G-CSF. As for signal transduction mediated by G-CSF receptor (G-CSFR), Stat3α was constitutively activated in wild-type WT1-infected 32D cl3 in response to G-CSF, whereas, in WT1-uninfected 32D cl3, activation of Stat3α was only transient. However, most interesting was the fact that G-CSF stimulation resulted in constitutive activation of Stat3β only in wild-type WT1-infected 32D cl3, but not in WT1-uninfected 32D cl3. Thus, WT1 expression constitutively activated both Stat3α and Stat3β. A transient activation of Stat1 was detected in both wild-type WT1-infected and uninfected 32D cl3 after G-CSF stimulation, but no difference in its activation was found. No activation of MAP kinase was detected in both wild-type WT1-infected and uninfected 32D cl3 after G-CSF stimulation. These results demonstrated that WT1 expression competed with the differentiation-inducing signal mediated by G-CSFR and constitutively activated Stat3, resulting in the blocking of differentiation and subsequent proliferation. Therefore, the data presented here support our hypothesis that the WT1 gene plays an essential role in leukemogenesis and performs an oncogenic function in hematopoietic progenitor cells and represent the first demonstration of an important role of the WT1 gene in signal transduction in hematopoietic progenitor cells.

scholarly journals Effects of Field Inoculation with VAM and Bacteria Consortia on Root Growth and Nutrients Uptake in Common Wheat

2018 ◽  
Vol 10 (9) ◽  
pp. 3286 ◽  
Author(s):  
Cristian Dal Cortivo ◽  
Giuseppe Barion ◽  
Manuel Ferrari ◽  
Giovanna Visioli ◽  
Lucia Dramis ◽  
...  
Keyword(s):  
Common Wheat ◽  
Root Length Density ◽  
N Uptake ◽  
Mycorrhizal Fungus ◽  
Growth Yield ◽  
N Fertilization ◽  
Environmental Benefits ◽  
Root Tip ◽  
Field Inoculation ◽  
N Dose

This study investigated the effects of a commercial biofertilizer containing the mycorrhizal fungus Rhizophagus irregularis and the diazotrophic N-fixing bacterium Azotobacter vinelandii on root and shoot growth, yield, and nutrient uptake in common wheat (Triticum aestivum L.) in order to improve the sustainable cultivation of this widespread crop. The trials were carried out in controlled conditions (rhizoboxes) and in open fields over two years to investigate the interaction between inoculation and three doses of nitrogen fertilization (160, 120 and 80 kg ha−1) in a silty-loam soil of the Po Plain (NE Italy). In rhizoboxes, efficient root colonization by R. irregularis was observed at 50 days after sowing with seed inoculation, together with improved root tip density and branching (+~30% vs. controls), while the effects of post-emergence inoculation by soil and foliar spraying were not observable at plant sampling. In the open, field spraying at end tillering significantly increased the volumetric root length density (RLD, +22% vs. controls) and root area density (+18%) after about two months (flowering stage) in both years under medium and high N fertilization doses, but not at the lowest N dose. In absence of inoculation, RLD progressively decreased with increased N doses. Inoculation had a negligible effect on grain yield and N uptake, which followed a typical N dose-response model, while straw Zn, P, and K concentrations were seldom improved. It is concluded that medium-high N fertilization doses are required to achieve the target yield and standards of quality (protein contents) in wheat cultivation, while the use of this mixed VAM-PGPR biofertilizer appears to be a sustainable mean for minimizing the adverse effects of chemical N fertilizers on root expansion and for improving the uptake of low-mobility nutrients, which has potentially relevant environmental benefits.

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