scholarly journals Nuclear Disposition of Alien Chromosome Introgressions into Wheat and Rye Using 3D-FISH

2019 ◽  
Vol 20 (17) ◽  
pp. 4143 ◽  
Author(s):  
Veronika Koláčková ◽  
Kateřina Perničková ◽  
Jan Vrána ◽  
Martin Duchoslav ◽  
Glyn Jenkins ◽  
...  
Keyword(s):  
Nuclear Periphery ◽  
The Other ◽  
Chromosome Territories ◽  
Alien Chromosome ◽  
Chromosome Domains ◽  
Partial Association ◽  
Somatic Tissues ◽  
Chromosome Arm ◽  
3D Fish ◽  
Genetically Determined

During interphase, the chromosomes of eukaryotes decondense and they occupy distinct regions of the nucleus, called chromosome domains or chromosome territories (CTs). In plants, the Rabl’s configuration, with telomeres at one pole of nucleus and centromeres at the other, appears to be common, at least in plants with large genomes. It is unclear whether individual chromosomes of plants adopt defined, genetically determined addresses within the nucleus, as is the case in mammals. In this study, the nuclear disposition of alien rye and barley chromosomes and chromosome arm introgressions into wheat while using 3D-FISH in various somatic tissues was analyzed. All of the introgressed chromosomes showed Rabl’s orientation, but their relative positions in the nuclei were less clear. While in most cases pairs of introgressed chromosomes occupied discrete positions, their association (proximity) along their entire lengths was rare, and partial association only marginally more frequent. This arrangement is relatively stable in various tissues and during various stages of the cell cycle. On the other hand, the length of a chromosome arm appears to play a role in its positioning in a nucleus: shorter chromosomes or chromosome arms tend to be located closer to the centre of the nucleus, while longer arms are more often positioned at the nuclear periphery.

scholarly journals Instability of Alien Chromosome Introgressions in Wheat Associated with Improper Positioning in the Nucleus

2019 ◽  
Vol 20 (6) ◽  
pp. 1448 ◽  
Author(s):  
Kateřina Perničková ◽  
Veronika Koláčková ◽  
Adam Lukaszewski ◽  
Chaolan Fan ◽  
Jan Vrána ◽  
...  
Keyword(s):  
Plant Breeding ◽  
Nuclear Periphery ◽  
Host Genome ◽  
Meiotic Pairing ◽  
Alien Chromosome ◽  
3D Fish ◽  
Meiotic Event ◽  
Metaphase I

Alien introgressions introduce beneficial alleles into existing crops and hence, are widely used in plant breeding. Generally, introgressed alien chromosomes show reduced meiotic pairing relative to the host genome, and may be eliminated over generations. Reduced pairing appears to result from a failure of some telomeres of alien chromosomes to incorporate into the leptotene bouquet at the onset of meiosis, thereby preventing chiasmate pairing. In this study, we analysed somatic nuclei of rye introgressions in wheat using 3D-FISH and found that while introgressed rye chromosomes or chromosome arms occupied discrete positions in the Rabl’s orientation similar to chromosomes of the wheat host, their telomeres frequently occupied positions away from the nuclear periphery. The frequencies of such abnormal telomere positioning were similar to the frequencies of out-of-bouquet telomere positioning at leptotene, and of pairing failure at metaphase I. This study indicates that improper positioning of alien chromosomes that leads to reduced pairing is not a strictly meiotic event but rather a consequence of a more systemic problem. Improper positioning in the nuclei probably impacts the ability of introgressed chromosomes to migrate into the telomere bouquet at the onset of meiosis, preventing synapsis and chiasma establishment, and leading to their gradual elimination over generations.

scholarly journals Activation of the lac Repressor in the Transgenic Mouse

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 297-304
Author(s):  
Heidi Scrable ◽  
Peter J Stambrook
Keyword(s):  
Copy Number ◽  
Methylation Status ◽  
Lac Repressor ◽  
The Other ◽  
Lac Operon ◽  
Normal Process ◽  
Divergent Sequence ◽  
Somatic Tissues ◽  
New Material ◽  
Bacterial Sequence

Abstract We have introduced sequences encoding the lac repressor of Escherichia coli into the genome of the mouse. One sequence was derived from the bacterial lac operon and the other was created by reencoding the amino acid sequence of lacI with mammalian codons. Both versions are driven by an identical promoter fragment derived from the human β-actin locus and were microinjected into genetically identical pronuclear stage embryos. All transgenes utilizing the bacterial coding sequence were transcriptionally silent in all somatic tissues tested. The sequence re-encoded with mammalian codons was transcriptionally active at all transgene loci and expressed ubiquitously. Using methylation-sensitive enzymes, we have determined the methylation status of lac repressor transgenes encoded by either the bacterial or mammalian sequence. The highly divergent bacterial sequence was hypermethylated at all transgene loci, while the mammalian sequence was only hypermethylated at a high copy number locus. This may reflect a normal process that protects the genome from acquiring new material that has an abnormally divergent sequence or structure.

scholarly journals EFFECTS OF CHRONIC EXCESS SALT INGESTION

1967 ◽  
Vol 126 (4) ◽  
pp. 687-699 ◽  
Author(s):  
Lewis K. Dahl ◽  
Knud D. Knudsen ◽  
Martha Heine ◽  
George Leitl
Keyword(s):  
Blood Pressure ◽  
Blood Pressure Response ◽  
Pressure Response ◽  
Sensitive Strain ◽  
The Other ◽  
Experimental Hypertension ◽  
Highly Sensitive ◽  
Blood Pressures ◽  
Genetically Determined ◽  
Resistant Animal

Parabiosis has been found to modify the expected blood pressure response of rats from two strains with opposite genetic propensities for experimental hypertension. When a member from one strain was united in parabiosis with a member from the other and both were maintained on high NaCl diet, the rat from the strain ordinarily resistant to it rapidly developed hypertension, in contrast to appropriate controls from this strain. The development of hypertension in this resistant animal preceded that in its mate from the strain highly sensitive to hypertension. In the latter, both the level of hypertension and mortality were significantly less than in its control. It seems likely that the hypertension observed is the resistant parabiont was initiated in its partner from the sensitive strain. This modification in blood pressures was not observed in the absence of a high NaCl diet. Parabiosis between animals from the same strain did not alter their response. Thus, as in earlier experiences (1–4) the interaction of a nongenetic factor (NaCl) with the appropriate genetic substrate appeared to be necessary for the development of hypertension. The findings are interpreted as evidence that a transmittable humoral influence plays an important role in the pathogenesis of rat hypertension. The presence of this agent is genetically determined but, under the conditions of these experiments, it took the added stimulus of dietary NaCl to demonstrate its existence.

Effect of hemoglobin type on the cardiorespiratory system of sheep

1965 ◽  
Vol 209 (3) ◽  
pp. 593-598 ◽  
Author(s):  
T. J. Dawson ◽  
J. V. Evans
Keyword(s):  
Oxygen Affinity ◽  
The Other ◽  
Domestic Sheep ◽  
Cardiorespiratory System ◽  
Hemoglobin Type ◽  
Lower Oxygen ◽  
Respiratory Systems ◽  
Genetically Determined ◽  
Theoretical Considerations

In domestic sheep there exist two genetically determined types of hemoglobin which have considerably different oxygen affinities. Under most conditions sheep with either of these hemoglobins exist together, apparently sheep with one type being at no gross disadvantage compared to those with the other. Theoretical considerations suggested that the tissues of sheep with the higher oxygen affinity hemoglobin (Hb-A) should be hypoxic relative to those of sheep with the lower oxygen affinity hemoglobin (Hb-B). The data obtained showed that the cardiovascular and respiratory systems of animals with different hemoglobins differed in many respects. It was concluded that the nature of these differences was such that they could be viewed as being due to adjustments by animals with Hb-A to alleviate the potential hypoxia of their tissues relative to the tissues of animals with Hb-B.

scholarly journals A new allele of the Gpi-1t temporal gene that regulates the expression of glucose phosphate isomerase in mouse oocytes

1984 ◽  
Vol 44 (2) ◽  
pp. 169-181 ◽  
Author(s):  
John D. West ◽  
Graham Fisher
Keyword(s):  
Cellulose Acetate ◽  
Structural Gene ◽  
The Other ◽  
Glucose Phosphate Isomerase ◽  
Cellulose Acetate Electrophoresis ◽  
Mouse Oocytes ◽  
Glucose Phosphate ◽  
Somatic Tissues ◽  
Developmental Programme

The dimeric enzyme glucose phosphate isomerase (GPI-1) is regulated in oocytes by a cis-acting temporal gene (Gpi-1t) that maps close to the structural gene (Gpi-1s). Quantitative cellulose acetate electrophoresis of GPI-1 allozymes from unfertilized eggs produced by various Gpi-1sa / Gpi-1sb heterozygous females revealed a new Gpi-1t allele that we have designated Gpi-1tc. This allele is present in 101/H mice and a partially congenie stock that carries the Gpi-lsa gene derived from the AKR strain. We have confirmed that Gpi-1tc is closely linked to Gpi-1s and that it is cis-acting. It produces higher levels of GPI-1 in unfertilized eggs than the other two Gpi-lt alleles that are known (Gpi-1ta and Gpi-1tb) but has no effect on GPI-1 in somatic tissues or spermatozoa. This new Gpi-1t allele represents a third developmental programme for GPI-1 expression in oocytes.

scholarly journals STUDIES ON BLOOD FACTORS RhA, RhB, AND RhC

1959 ◽  
Vol 110 (4) ◽  
pp. 495-510 ◽  
Author(s):  
Lester J. Unger ◽  
Alexander S. Wiener ◽  
L. Katz
Keyword(s):  
Large Series ◽  
The Other ◽  
Other Hand ◽  
Genetically Determined ◽  
Transfusion Reactions ◽  
Blood Factors ◽  
Clinical Cases

Observations are described of the incidence among Caucasians and Negroes of the blood factors RhA, RhB and RhC which occur associated with the Rh0 factor in typical Rh-positive blood. The antiserums used for the tests were derived from Rh-positive patients who had had hemolytic transfusion reactions or erythroblastotic babies. Among a large series of individuals, it was found that only rarely is any of the blood factors RhA, RhB, or RhC lacking from "standard" Rh0-positive blood. On the other hand, about half of the specimens of Rh0 variant blood lack one or more of the factors RhA, RhB, and RhC, which, when present in such blood, are also almost always variants. Judging from the incidence of specimens lacking one or more of these factors, RhA, RhB, and RhB appear to be relatively independent of one another despite their association with blood factor Rh0. Tests for factors RhA, RhB, and RhC distinguish new rare varieties of Rh and ℜh agglutinogens, each genetically determined by corresponding allelic genes. There is no doubt that more clinical cases will be found in which sensitized Rh-positive individuals have antibodies resembling anti-Rh0 in specificity. Four such cases have already been studied by the present authors, and in each case the antibodies were shown to be different from anti-Rh0 in specificity. Since they were also different from one another, they have been assigned the symbols anti-RhA, anti-RhB, anti-RhC, and anti-RhD, respectively, the first three being the antiserums used in the present study. Obviously, in order to avoid confusion of nomenclature, the specificity of antiserums from other similar cases will have to be compared with anti-RhA, anti-RhB, anti-RhC, and anti-RhD and shown to be different from all four, as well as anti-Rh0, before a distinctive symbol is assigned to them.

High resolution analysis of interphase chromosome domains

2000 ◽  
Vol 113 (14) ◽  
pp. 2585-2593 ◽  
Author(s):  
A.E. Visser ◽  
F. Jaunin ◽  
S. Fakan ◽  
J.A. Aten
Keyword(s):  
High Resolution ◽  
Close Contact ◽  
Chinese Hamster ◽  
Chromosome Territories ◽  
Interphase Chromosome ◽  
Cell Cycles ◽  
Chromosome Domains ◽  
High Resolution Analysis ◽  
Interchromatin Space

Chromosome territories need to be well defined at high resolution before functional aspects of chromosome organization in interphase can be explored. To visualize chromosomes by electron microscopy (EM), the DNA of Chinese hamster fibroblasts was labeled in vivo with thymidine analogue BrdU. Labeled chromosomes were then segregated during several cell cycles to obtain nuclei containing only 2 to 3 labeled chromosomes. Subsequent immunocytochemical detection of BrdU allowed analysis by EM of chromosome territories and subchromosomal domains in well preserved nuclei. Our results provide the first high resolution visualization of chromosomes in interphase nuclei. We show that chromosome domains are either separated from one another by interchromatin space or are in close contact with no or little intermingling of their DNA. This demonstrates that, while chromosomes form discrete territories, chromatin of adjacent chromosomes may be in contact in limited regions, thus implying chromosome-chromosome interactions. Chromosomes are organized as condensed chromatin with dispersed chromatin extending into the interchromatin space that is largely devoid of DNA. The interchromatin space, which is known to be involved in various nuclear functions, forms interconnecting channels running through and around chromosome territories. Functional implications of this organization are discussed.

scholarly journals Histone H3 lysine 56 acetylation by Rtt109 is crucial for chromosome positioning

2008 ◽  
Vol 183 (4) ◽  
pp. 641-651 ◽  
Author(s):  
Shin-ichiro Hiraga ◽  
Sotirios Botsios ◽  
Anne D. Donaldson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Histone Acetyltransferase ◽  
Nuclear Periphery ◽  
Histone H3 ◽  
Epigenetic Inheritance ◽  
S Phase ◽  
Chromosome Localization ◽  
Chromosome Domains ◽  
H3k56 Acetylation

Correct intranuclear organization of chromosomes is crucial for many genome functions, but the mechanisms that position chromatin are not well understood. We used a layered screen to identify Saccharomyces cerevisiae mutants defective in telomere localization to the nuclear periphery. We find that events in S phase are crucial for correct telomere localization. In particular, the histone chaperone Asf1 functions in telomere peripheral positioning. Asf1 stimulates acetylation of histone H3 lysine 56 (H3K56) by the histone acetyltransferase Rtt109. Analysis of rtt109Δ and H3K56 mutants suggests that the acetylation/deacetylation cycle of the H3K56 residue is required for proper telomere localization. The function of H3K56 acetylation in localizing chromosome domains is not confined to telomeres because deletion of RTT109 also prevents the correct peripheral localization of a newly identified S. cerevisiae “chromosome-organizing clamp” locus. Because chromosome positioning is subject to epigenetic inheritance, H3K56 acetylation may mediate correct chromosome localization by facilitating accurate transmission of chromatin status during DNA replication.

scholarly journals Chromosome arm length and nuclear constraints determine the dynamic relationship of yeast subtelomeres

2010 ◽  
Vol 107 (5) ◽  
pp. 2025-2030 ◽  
Author(s):  
Pierre Therizols ◽  
Tarn Duong ◽  
Bernard Dujon ◽  
Christophe Zimmer ◽  
Emmanuelle Fabre
Keyword(s):  
Nuclear Periphery ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Cells ◽  
Nuclear Space ◽  
Microtubule Organizing Center ◽  
Physical Constraints ◽  
Dynamic Relationship ◽  
Chromosome Arm

Physical interactions between distinct chromosomal genomic loci are important for genomic functions including recombination and gene expression, but the mechanisms by which these interactions occur remain obscure. Using telomeric association as a model system, we analyzed here the in vivo organization of chromosome ends of haploid yeast cells during interphase. We separately labeled most of the 32 subtelomeres and analyzed their positions both in nuclear space and relative to three representative reference subtelomeres by high-throughput 3D microscopy and image processing. We show that subtelomeres are positioned nonrandomly at the nuclear periphery, depending on the genomic size of their chromosome arm, centromere attachment to the microtubule organizing center (spindle pole body, SPB), and the volume of the nucleolus. The distance of subtelomeres to the SPB increases consistently with chromosome arm length up to ≈300 kb; for larger arms the influence of chromosome arm length is weaker, but the effect of the nucleolar volume is stronger. Distances between pairs of subtelomeres also exhibit arm-length dependence and suggest, together with dynamic tracking experiments, that potential associations between subtelomeres are unexpectedly infrequent and transient. Our results suggest that interactions between subtelomeres are nonspecific and instead governed by physical constraints, including chromosome structure, attachment to the SPB, and nuclear crowding.

Relation Between Body Fat and Glycogen Levels of Inbred Strains of Mice

1958 ◽  
Vol 195 (3) ◽  
pp. 681-684 ◽  
Author(s):  
John B. Lyon
Keyword(s):  
Body Fat ◽  
Muscle Glycogen ◽  
Inbred Strains ◽  
The Other ◽  
Small Animals ◽  
Inverse Relation ◽  
Inbred Strains Of Mice ◽  
Fat Stores ◽  
Genetically Determined ◽  
Old Mice

Previous studies suggested that an inverse relation existed between concentrations of body fat and muscle glycogen among inbred strains of mice. Of six strains, one, the I strain, was resistant to obesity, and the levels of muscle glycogen were 3–6 times greater than those of the other five strains. Because the tentative proposal was based on data from only one lean strain, mice of the DBA strain were studied as another possible lean strain. Although small animals, sublines 1 and 2 of this strain became obese when fed a 50% fat diet, and the levels of muscle glycogen were in the range of the other five obese strains. It was also found that concentrations of body fat up to 25% could be induced in 4–5-month-old mice of the I strain, and by dietary means alone. The concentrations of muscle glucogen in these mice were not lower than those of I strain mice exhibiting concentrations of body fat of 11%. It was concluded, therefore, that an inverse relation between carbohydrate and fat stores does not exist among inbred strains of mice. The unusually high levels of muscle glycogen in the I strain appear to be unique, and are most likely genetically determined.

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