A guide for in-house design of template-switch-based 5' rapid amplification of cDNA ends systems.

Rapid amplification of cDNA ends (RACE) is an established strategy used to determine the transcription start point(s) and the 5' untranslated region(s) of mRNA. Different approaches to perform 5' RACE are available, and one particularly simple and powerful strategy is based on a phenomenon called template-switching. We investigated different aspects of template-switch-based 5' RACE, and we describe the different steps leading to the in-house development of a complete 5' RACE system-from oligonucleotide design to polymerase chain reaction (PCR) amplification. We show that the resulting system is reliable, time-efficient, and inexpensive.

Analysis of current and alternative phenol based RNA extraction methodologies for cyanobacteria.

BACKGROUND: The validity and reproducibility of gene expression studies depend on the quality of extracted RNA and the degree of genomic DNA contamination. Cyanobacteria are gram-negative prokaryotes that synthesize chlorophyll a and carry out photosynthetic water oxidation. These organisms possess an extended array of secondary metabolites that impair cell lysis, presenting particular challenges when it comes to nucleic acid isolation. Therefore, we used the NHM5 strain of Nostoc punctiforme ATCC 29133 to compare and improve existing phenol based chemistry and procedures for RNA extraction. RESULTS: With this work we identify and explore strategies for improved and lower cost high quality RNA isolation from cyanobacteria. All the methods studied are suitable for RNA isolation and its use for downstream applications. We analyse different Trizol based protocols, introduce procedural changes and describe an alternative RNA extraction solution. CONCLUSION: It was possible to improve purity of isolated RNA by modifying protocol procedures. Further improvements, both in RNA purity and experimental cost, were achieved by using a new extraction solution, PGTX.

Webtag: a new web tool providing tags/anchors for RT-PCR experiments with prokaryotes.

BACKGROUND: Webtag is a tool providing oligonucleotide sequences (usually called tags or anchors) that are absent from a specified genome. These tags/anchors can be appended to gene specific primers for reverse transcriptase polymerase chain reaction experiments, circumventing genomic DNA contamination. RESULTS: The use of a relational database, in conjunction with a series of scripts written in PHP and Perl, allows the user to rapidly obtain tags that are: 1) suitable for a specific organism, and 2) compatible with other oligonucleotides to be used in the experimental procedures. CONCLUSION: This new web tool allows scientists to easily and rapidly obtain suitable tags for RT-PCR experiments, and is available at http://www.egs.uu.se/software/webtag/.

Generation of non-genomic oligonucleotide tag sequences for RNA template-specific PCR.

BACKGROUND: In order to overcome genomic DNA contamination in transcriptional studies, reverse template-specific polymerase chain reaction, a modification of reverse transcriptase polymerase chain reaction, is used. The possibility of using tags whose sequences are not found in the genome further improves reverse specific polymerase chain reaction experiments. Given the absence of software available to produce genome suitable tags, a simple tool to fulfill such need was developed. RESULTS: The program was developed in Perl, with separate use of the basic local alignment search tool, making the tool platform independent (known to run on Windows XP and Linux). In order to test the performance of the generated tags, several molecular experiments were performed. The results show that Tagenerator is capable of generating tags with good priming properties, which will deliberately not result in PCR amplification of genomic DNA. CONCLUSION: The program Tagenerator is capable of generating tag sequences that combine genome absence with good priming properties for RT-PCR based experiments, circumventing the effects of genomic DNA contamination in an RNA sample.