scholarly journals High-resolution FEISEM detection of DNA centromeric probes in HeLa metaphase chromosomes.

1995 ◽  
Vol 43 (4) ◽  
pp. 413-419 ◽  
Author(s):  
E Rizzi ◽  
M Falconi ◽  
R Rizzoli ◽  
B Baratta ◽  
L Manzoli ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
High Resolution ◽  
Centromeric Region ◽  
Secondary Electron Emission ◽  
Dna Probes ◽  
Dna Denaturation ◽  
Metaphase Chromosomes ◽  
Chromatin Arrangement ◽  
Fiber Organization

HeLa metaphase chromosome spreads were hybridized with centromeric biotinylated DNA probes and detected with gold-conjugated anti-biotin antibodies. Chromosomes were observed by an in-lens field emission scanning electron microscope (FEISEM), which permits detection of biological samples without any coating. DNA probes were well localized in the centromeric region of chromosomes and there was clear discrimination between 10 nm fibers that hybridized to DNA probes and those that did not hybridize. This approach shows that in situ hybridization can be directly visualized at the FEISEM level by evaluating only secondary electron emission, which allows physical localization of the hybridized probe with high resolution so that backscatter detection represents only a control. Because chromosomes maintain the 10-nm fiber organization after in situ hybridization procedures, our data suggest that this fiber represents the lowest order of chromatin arrangement that permits transitory DNA denaturation.

Histochemical aspects of nucleic acid detection

1995 ◽  
Vol 53 ◽  
pp. 746-747
Author(s):  
B. A. Hamkalo ◽  
Elizabeth R. Unger
Keyword(s):  
In Situ Hybridization ◽  
Nucleic Acid ◽  
High Resolution ◽  
Dna Sequences ◽  
Single Copy ◽  
Nucleic Acid Detection ◽  
Metaphase Chromosomes ◽  
Potential Applications ◽  
Nucleic Acid Sequences

This symposium brings together several approaches for the detection of specific nucleic acid sequences that have potential applications at the histochemical level.Trask et al. report on the use of fluorescence in situ hybridization (FISH) techniques to study the arrangement of DNA sequences in normal and diseaserelated chromosomes. The sites of specific DNA sequences can be fluorescently tagged. Different sequences can be labeled with different fluorochromes so that their arrangement can be studied using fluorescence microscopy. The distances between points on the same or different chromosomes can be determined in a large number of interphase nuclei or metaphase chromosomes. A variety of probe types, ranging from single-copy sequences to highly repeated sequences can be employed.Hamkalo and co-workers have used non-radioactive methods at the EM level for the detection of nucleic acid sequences by in situ hybridization. Analysis of metaphase chromosomes by electron microscopy allows for high resolution mapping of chromosomes. A variety of labelling procedures have been employed to illustrate the utility of high resolution nucleic acid sequence mapping in these preparations.

Eukaryotic genome organization analyzed by electron microscope in situ hybridization

1991 ◽  
Vol 49 ◽  
pp. 40-41
Author(s):  
Barbara A. Hamkalo ◽  
Sandya Narayanswami ◽  
Nadja Dvorkin
Keyword(s):  
In Situ Hybridization ◽  
Electron Microscope ◽  
Genome Organization ◽  
Cell Biology ◽  
Eukaryotic Genome ◽  
Dna Denaturation ◽  
Metaphase Chromosomes ◽  
Rna Sequences ◽  
Gold Particles

In situ hybridization is a powerful tool for the localization of DNA/RNA sequences in nuclei and chromosomes. The introduction of nonisotopic labelling methodologies in conjunction with fluorescent or enzyme-linked detection have resulted in a dramatic increase in the application of this technique at the light microscope (LM) level and has placed it in a pivotal role in cell biology, development and genetics. Development of equivalent mapping protocols at the EM level offers increased spatial resolution. We have combined the use of nonisotopic probes with invmunogold labelling to investigate eukaryotic genome organization at high resolution.Metaphase chromosomes released from mitotically-arrested cells are deposited on gold EM grids by centrifugation through a sucrose cushion. After fixation (0.1% glutaraldehyde, 20 min) and DNA denaturation, chromosomes are hybridized to cloned probes enzymatically labelled with biotin-dUTP, digoxigenin-dUTP, dinitrophenyl-dUTP or covalently coupled to N-acetoxyacetoaminofluorene. Hybrid sites typically are detected by a two-step antibody incubation and 1-30 nm colloidal gold particles.

A Simplified Combination of DNA Probe Preparation and Fluorescence in situ Hybridization

1992 ◽  
Vol 47 (9-10) ◽  
pp. 739-747 ◽  
Author(s):  
Dino Celeda ◽  
Ulrich Bettag ◽  
Christoph Cremer
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Repetitive Dna ◽  
Human Lymphocytes ◽  
Dna Probes ◽  
Dna Probe ◽  
Nick Translation ◽  
Metaphase Chromosomes ◽  
Human Dna

Fluorescence in situ hybridization (FISH) has found widespread applications in cytogenetics. So far the standard protocols for probe amplification (and simultaneous labeling) by PCR, nick translation and in situ hybridization involve different buffer systems leading to a number of time consuming washing steps even before hybridization. In this manuscript we show a fast technique of a close combination of DNA probe preparation and in situ hybridization (ISH). This method was applied to metaphase chromosomes from human lymphocytes fixed on slides. Two specific repetitive DNA probes, the pUC 1.77 DNA probe and the DYZ 1 repetitive DNA fraction were used, amplified and labeled in different ways. Additional experiments with total genomic male human DNA as the DNA probe suggest that this method may be extended to a large variety of other probes. Moreover the ISH technique described does not require toxic denaturing agents, such as formamide.

DNA sequence mapping in interphase and metaphase chromosomes by fluorescence in situ hybridization

1992 ◽  
Vol 50 (1) ◽  
pp. 496-497
Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequence ◽  
Dna Sequences ◽  
Dual Band ◽  
Nick Translation ◽  
Metaphase Chromosomes ◽  
Band Pass ◽  
Texas Red ◽  
Fluorescent Spot

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.

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