Human miRNA MicroArray design
The design of MiRanalyser miRNA MicroArrays is similar to that of other spotted oligonucleotide MicroArrays, with the two major differences:
- The short sequence of miRNA restricts the flexibility to design specific and long probe.
- The wide range of GC content and melting temperatures of miRNA sequences present an unsatisfactory probe set for MicroArrays.
To overcome this limitation and in order to balance the melting temperature of different miRNA sequences we adopted the strategy by either incorporating chemically LNA® modified nucleotide to the oligonucleotide sequence of miRNA or to shorten the length of miRNA sequences with high GC content.
The MiRanalyser MicroArrays are manufactured by printing the complete set of miRNA in duplicate on standard 75 x 25 x 1 mm microscope glass slides from Corning® ULTRA GAPS II slides which are compatible with the most commonly used MicroArray scanning and hybridization equipment.
The MiRanalyser MicroArray contains two identical fields per glass slide, each could be hybridized separately by mono-colour or two-colour fluorescence-based MicroArray technologies. The two identical fields within single slide could be also used for dyes swap experiments.
Human MiRanalyser MicroArray content
- The sequences of human miRNA are based on Sanger miRBase Database. The content of the MiRanalyser MicroArray is updated as soon as new miRNA sequences are validated and publicly available.
- The LNA® containing oligo set for human are carefully designed for optimal hybridization and for stringent washing conditions.
- The probes are 18–24 nt length and they are targeting a known miRNA and containing LNA® modification for increased binding specificity and signal intensities.
- The oligo sets are synthesized, HPLC purified and controlled by Mass Spectrometry analysis to remove any trace of truncated oligonucleotides.
- Endogenous gene controls: Small human U6 rRNA and 5S rRNA are included in the MicroArray and can be used as endogenous control. The MicroArray contains Hydroxymethylbilane synthase (HMBS) and TATA box binding protein (TBP) probes.
- Exogenous gene controls: The human MiRanalyser MicroArray includes 5 spike-in controls. The nucleotide sequences of 5 oligonucleotides of 20 bases which are not found in human, mice and rat genomes where synthetised and incorporated to the MicroArray: The package includes 5 spike-in synthetic RNA.