Cargando…
Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis
BACKGROUND: In situ detection of short sequence elements in genomic DNA requires short probes with high molecular resolution and powerful specific signal amplification. Padlock probes can differentiate single base variations. Ligated padlock probes can be amplified in situ by rolling circle DNA synt...
Autores principales: | , , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2007
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2212658/ https://www.ncbi.nlm.nih.gov/pubmed/17997865 http://dx.doi.org/10.1186/1471-2199-8-103 |
_version_ | 1782148738891907072 |
---|---|
author | Lohmann, Jakob S Stougaard, Magnus Koch, Jørn |
author_facet | Lohmann, Jakob S Stougaard, Magnus Koch, Jørn |
author_sort | Lohmann, Jakob S |
collection | PubMed |
description | BACKGROUND: In situ detection of short sequence elements in genomic DNA requires short probes with high molecular resolution and powerful specific signal amplification. Padlock probes can differentiate single base variations. Ligated padlock probes can be amplified in situ by rolling circle DNA synthesis and detected by fluorescence microscopy, thus enhancing PRINS type reactions, where localized DNA synthesis reports on the position of hybridization targets, to potentially reveal the binding of single oligonucleotide-size probe molecules. Such a system has been presented for the detection of mitochondrial DNA in fixed cells, whereas attempts to apply rolling circle detection to metaphase chromosomes have previously failed, according to the literature. METHODS: Synchronized cultured cells were fixed with methanol/acetic acid to prepare chromosome spreads in teflon-coated diagnostic well-slides. Apart from the slide format and the chromosome spreading everything was done essentially according to standard protocols. Hybridization targets were detected in situ with padlock probes, which were ligated and amplified using target primed rolling circle DNA synthesis, and detected by fluorescence labeling. RESULTS: An optimized protocol for the spreading of condensed metaphase chromosomes in teflon-coated diagnostic well-slides was developed. Applying this protocol we generated specimens for target primed rolling circle DNA synthesis of padlock probes recognizing a 40 nucleotide sequence in the male specific repetitive satellite I sequence (DYZ1) on the Y-chromosome and a 32 nucleotide sequence in the repetitive kringle IV domain in the apolipoprotein(a) gene positioned on the long arm of chromosome 6. These targets were detected with good efficiency, but the efficiency on other target sites was unsatisfactory. CONCLUSION: Our aim was to test the applicability of the method used on mitochondrial DNA to the analysis of nuclear genomes, in particular as represented by metaphase spreads. An optimized protocol for chromosome spreading in diagnostic well-slides was used for the detection of circularized padlock probes amplified by target primed rolling circle DNA synthesis from condensed metaphase chromosomes. We were able to detect a 40 nucleotide sequence in the male specific repetitive satellite I sequence and a 32 nucleotide sequence in the repetitive kringle IV domain in the apolipoprotein(a) gene. Our overall conclusion is that whilst this type of reaction indeed can be brought to work on nuclear genomes, including metaphase chromosomes, the total efficiency of this multistep reaction is at present relatively low (1–10% of target sites picked up), meaning that it is best suited for the detection of targets that exist in multiple copies per cell. Changing this will require substantial efforts to systematically increase the efficiency in each step. |
format | Text |
id | pubmed-2212658 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-22126582008-01-24 Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis Lohmann, Jakob S Stougaard, Magnus Koch, Jørn BMC Mol Biol Methodology Article BACKGROUND: In situ detection of short sequence elements in genomic DNA requires short probes with high molecular resolution and powerful specific signal amplification. Padlock probes can differentiate single base variations. Ligated padlock probes can be amplified in situ by rolling circle DNA synthesis and detected by fluorescence microscopy, thus enhancing PRINS type reactions, where localized DNA synthesis reports on the position of hybridization targets, to potentially reveal the binding of single oligonucleotide-size probe molecules. Such a system has been presented for the detection of mitochondrial DNA in fixed cells, whereas attempts to apply rolling circle detection to metaphase chromosomes have previously failed, according to the literature. METHODS: Synchronized cultured cells were fixed with methanol/acetic acid to prepare chromosome spreads in teflon-coated diagnostic well-slides. Apart from the slide format and the chromosome spreading everything was done essentially according to standard protocols. Hybridization targets were detected in situ with padlock probes, which were ligated and amplified using target primed rolling circle DNA synthesis, and detected by fluorescence labeling. RESULTS: An optimized protocol for the spreading of condensed metaphase chromosomes in teflon-coated diagnostic well-slides was developed. Applying this protocol we generated specimens for target primed rolling circle DNA synthesis of padlock probes recognizing a 40 nucleotide sequence in the male specific repetitive satellite I sequence (DYZ1) on the Y-chromosome and a 32 nucleotide sequence in the repetitive kringle IV domain in the apolipoprotein(a) gene positioned on the long arm of chromosome 6. These targets were detected with good efficiency, but the efficiency on other target sites was unsatisfactory. CONCLUSION: Our aim was to test the applicability of the method used on mitochondrial DNA to the analysis of nuclear genomes, in particular as represented by metaphase spreads. An optimized protocol for chromosome spreading in diagnostic well-slides was used for the detection of circularized padlock probes amplified by target primed rolling circle DNA synthesis from condensed metaphase chromosomes. We were able to detect a 40 nucleotide sequence in the male specific repetitive satellite I sequence and a 32 nucleotide sequence in the repetitive kringle IV domain in the apolipoprotein(a) gene. Our overall conclusion is that whilst this type of reaction indeed can be brought to work on nuclear genomes, including metaphase chromosomes, the total efficiency of this multistep reaction is at present relatively low (1–10% of target sites picked up), meaning that it is best suited for the detection of targets that exist in multiple copies per cell. Changing this will require substantial efforts to systematically increase the efficiency in each step. BioMed Central 2007-11-13 /pmc/articles/PMC2212658/ /pubmed/17997865 http://dx.doi.org/10.1186/1471-2199-8-103 Text en Copyright © 2007 Lohmann et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Methodology Article Lohmann, Jakob S Stougaard, Magnus Koch, Jørn Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title | Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title_full | Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title_fullStr | Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title_full_unstemmed | Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title_short | Detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle DNA synthesis |
title_sort | detection of short repeated genomic sequences on metaphase chromosomes using padlock probes and target primed rolling circle dna synthesis |
topic | Methodology Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2212658/ https://www.ncbi.nlm.nih.gov/pubmed/17997865 http://dx.doi.org/10.1186/1471-2199-8-103 |
work_keys_str_mv | AT lohmannjakobs detectionofshortrepeatedgenomicsequencesonmetaphasechromosomesusingpadlockprobesandtargetprimedrollingcirclednasynthesis AT stougaardmagnus detectionofshortrepeatedgenomicsequencesonmetaphasechromosomesusingpadlockprobesandtargetprimedrollingcirclednasynthesis AT kochjørn detectionofshortrepeatedgenomicsequencesonmetaphasechromosomesusingpadlockprobesandtargetprimedrollingcirclednasynthesis |