Chromosome Banding and Heterochromatin in Vicia Faba

10.26686/wgtn.16958767.v1 ◽

2021 ◽

Author(s):

◽

Roland Elliston Rowland

Keyword(s):

Vicia Faba ◽

Acid Treatment ◽

Secondary Constriction ◽

Cold Treatment ◽

Root Tip ◽

Late Replication ◽

Chromosomal Dna ◽

Variable Expression ◽

Chromosome Segments

<p>This study documents the distribution of bands in Vicia faba root-tip chromosomes as shown by acid treatment, quinacrine mustard fluorescence, various forms of Giemsa banding and orcein banding methods, and demonstrates the coincidence of these bands with the position of heterochromatin as shown by cold treatment and late replication. Heterochromatin in the large metacentric M chromosome is located in two areas: (a) around the centromere and (b) adjacent to the secondary constriction. The latter is not late-replicating but is judged to represent classical nucleolus-associated heterochromatin. Heterochromatin in the smaller sub-telocentric S chromosomes is located in the intercalary and proximal areas of their long arms and in the short arm of two chromosomes. The variable expression of particular chromosome segments with different banding techniques testifies to certain differences between heterochromatic regions and emphasizes the existence of several classes of heterochromatin. In situ molecular hybridization of labelled complementary RNA to chromosomal DNA indicates the presence of repetitive DNA in both euchromatin and heterochromatin of the V. faba genome.</p>

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Highly effective cell synchronization in plant roots by hydroxyurea and amiprophos-methyl or colchicine

Genome ◽

10.1139/g93-053 ◽

1993 ◽

Vol 36 (2) ◽

pp. 387-390 ◽

Cited By ~ 52

Author(s):

W. H. Pan ◽

A. Houben ◽

R. Schlegel

Keyword(s):

Dna Hybridization ◽

Enzymatic Digestion ◽

Root Tip ◽

Chromosomal Dna ◽

Cell Synchronization ◽

Ice Water ◽

Minimum Distortion ◽

Barley Cell ◽

Chromosome Spreading

Effective somatic cell synchronization in root-tip meristems and improved chromosome spreading were achieved in white campion, wheat, rye, and barley by application of hydroxyurea and amiprophos-methyl or colchicine, combined with a pretreatment of ice water and modified fixative, as well as enzymatic digestion of the meristems. The protocol provides metaphase indices of approximately 50%. The chromosomes and chromosomal DNA were with minimum distortion, providing useful material for chromosome banding studies, in situ DNA–DNA hybridization, microdissection, and microcloning.Key words: Melandrium album, rye, wheat, barley, cell cycle, root meristem, synchronization, metaphase index, chromosome preparation.

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Microfluidic extraction and stretching of chromosomal DNA from single cell nuclei for DNA fluorescence in situ hybridization

Biomedical Microdevices ◽

10.1007/s10544-011-9621-8 ◽

2012 ◽

Vol 14 (3) ◽

pp. 443-451 ◽

Cited By ~ 10

Author(s):

Xiaozhu Wang ◽

Shin-ichiro Takebayashi ◽

Evans Bernardin ◽

David M. Gilbert ◽

Ravindran Chella ◽

...

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Single Cell ◽

Cell Nuclei ◽

Chromosomal Dna

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GAA Trinucleotide Repeat Region Regulates M9/pMGA Gene Expression in Mycoplasma gallisepticum

Infection and Immunity ◽

10.1128/iai.68.2.871-876.2000 ◽

2000 ◽

Vol 68 (2) ◽

pp. 871-876 ◽

Cited By ~ 34

Author(s):

Li Liu ◽

Kevin Dybvig ◽

Victor S. Panangala ◽

Vicky L. van Santen ◽

Christopher T. French

Keyword(s):

Gene Expression ◽

Trinucleotide Repeat ◽

Mycoplasma Gallisepticum ◽

Avian Host ◽

Phase Variable ◽

Repeat Region ◽

Chromosomal Dna ◽

Promoter Regions ◽

Variable Expression ◽

Gaa Repeats

ABSTRACT Mycoplasma gallisepticum, the cause of chronic respiratory infections in the avian host, possesses a family of M9/pMGA genes encoding an adhesin(s) associated with hemagglutination. Nucleotide sequences of M9/pMGA gene family members indicate extensive sequence similarity in the promoter regions of both the transcribed and silent genes. The mechanism that regulates M9/pMGA gene expression is unknown, but studies have revealed an apparent correlation between gene expression and the number of tandem GAA repeat motifs located upstream of the putative promoter. In this study, transposon Tn4001was used as a vector with the Escherichia coli lacZ gene as the reporter system to examine the role of the GAA repeats in M9/pMGA gene expression in M. gallisepticum. A 336-bp M9 gene fragment (containing the GAA repeat region, the promoter, and the translation start codon) was amplified by PCR, ligated with alacZ gene from E. coli, and inserted into the Tn4001-containing plasmid pISM2062. This construct was transformed into M. gallisepticum PG31. Transformants were filter cloned on agar supplemented with 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside (X-Gal) to monitor lacZ gene expression on the basis of blue/white color selection. Several cycles of filter cloning resulted in cell lineages in which lacZ gene expression alternated between the On and Off states in successive generations of progeny clones. The promoter regions of the M9-lacZ hybrid genes of individual progeny clones were amplified by PCR and sequenced. The only differences between the promoter regions of the blue and white colonies were in the number of GAA repeats. Clones that expressedlacZ had exactly 12 tandem copies of the GAA repeat. Clones that did not express lacZ invariably had either more than 12 (14 to 16) or fewer than 12 (5 to 11) GAA repeats. Southern analysis of M. gallisepticum chromosomal DNA confirmed that the phase-variable expression of the lacZ reporter gene was not caused by Tn4001 transposition. These data strongly indicate that changes in the length of the GAA repeat region are responsible for regulating M9/pMGA gene expression.

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C-banding and fluorescence in situ hybridization studies of the wheat–alien hybrid 'Agrotana'

Genome ◽

10.1139/g94-066 ◽

1994 ◽

Vol 37 (3) ◽

pp. 477-481 ◽

Cited By ~ 13

Author(s):

Jie Xu ◽

R. L. Conner ◽

A. Laroche

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Genomic Dna ◽

Chromosome Engineering ◽

C Banding ◽

Chinese Spring Wheat ◽

Mother Cells ◽

Alien Chromatin ◽

Chromosome Segments

'Agrotana', a wheat-alien hybrid (2n = 56), is a potential source of resistance to common root rot, stem rust, wheat streak mosaic virus, and the wheat curl mite. However, the origin of 'Agrotana', reported to be durum wheat × Agropyron trichophorum (pubescent wheatgrass), is uncertain. The objective of this investigation was to determine the chromosome constitution of 'Agrotana' using C-banding and fluorescence in situ hybridization techniques. The F1 hybrid of 'Agrotana' × 'Chinese Spring' wheat showed 7 I + 21 II in 14.9% of the pollen mother cells, evidence of the presence of the A, B, and D genomes in 'Agrotana'. The hybrid had 16 heavily C-banded chromosomes, namely 4A, and 1-7B of wheat, and a translocation that probably involved wheat chromosomes 2A and 2D. In situ hybridization using biotinylated genomic DNA of Ag. trichophorum cv. Greenleaf blocked with CS DNA failed to identify the alien chromosomes in 'Agrotana', indicating that the alien chromosomes were not likely derived from pubescent wheatgrass. In situ hybridization using labelled wheat genomic DNA blocked with 'Agrotana' DNA revealed that 'Agrotana' had 40 wheat, 14 alien, and 2 (a pair) wheat–alien translocated chromosomes. There was no homology between wheat and the alien chromosomes or chromosome segments involved in the wheat–alien recombinant. Two of the seven pairs of alien chromosomes were homoeologous to each other. The ability to identify alien chromatin in wheat using labelled wheat DNA instead of labelled alien DNA will be particularly useful in chromosome engineering of wheat germplasms having alien chromatin of unknown origin.Key words: wheat–alien hybrid, C-banding, fluorescence in situ hybridization, labelled wheat DNA as probe.

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