I am getting DNA contamination after mRNA isolation using Dynabeads magnetic beads. Why is this?
There are several reasons why DNA contamination may occur:
- Incomplete DNA shearing.
- Incomplete removal of sample lysate after the hybridization step.
- Insufficient washing and/or removal of wash buffers.
- The ratio of sample to beads was too high.
I am getting rRNA contamination after mRNA isolation using Dynabeads magnetic beads. What should I do?
Ribosomal RNA is effectively eliminated by reextracting the mRNA from the eluate. Reuse the same Dynabeads Oligo(dT)25 beads that were used for the original isolation. Wash the beads twice in Washing Buffer B. Dilute the eluted mRNA with 4 times its volume of Lysis/Binding Buffer, then add the beads. Incubate with mixing at room temperature for 3-5 minutes, then continue with the Direct mRNA Isolation Protocol.
How long can I leave the isolated mRNA on Dynabeads Oligo(dT)25 magnetic beads?
We recommend immediate use of Dynabeads magnetic beads-mRNA complex or eluted mRNA for cDNA synthesis, in RT-PCR, or for other downstream applications. If storage is needed, we recommend you elute the mRNA from the beads using 10 mM Tris-HCl buffer (pH 7.5) and freeze it(-80°C). It is very important that all equipment and samples are RNase free.
My Dynabeads magnetic beads are not pelleting well with the magnet. Do you have any suggestions for me?
Please review the following possibilities for why your Dynabeads magnetic beads are not pelleting:
- The solution is too viscous.
- The beads have formed aggregates because of protein-protein interaction.
Try these suggestions:
- Increase separation time (leave tub on magnet for 2-5 minutes)
- Add DNase I to the lysate (~0.01 mg/mL)
- Increase the Tween 20 concentration to ~0.05% of the binding and/or washing buffer.
- Add up to 20 mM beta-merecaptoethanol to the binding and/or wash buffers.
Can I use Dynabeads Oligo(dT)25 magnetic beads in real-time PCR?
Dynabeads magnetic beads are compatible with TaqMan real-time PCR chemistry and non-capillary real-time PRC instruments. However, Dynabeads magnetic beads exhibit a low level of autofluorescence that can increase the intensity of the fluorescent signal to some degree. This can be compensated for by using a Dynabeads magnetic beads and water background in the instrument. Then background signal intensity can be subtracted from the sample signal intensity in all subsequent real-time PCR experiments containing Dynabeads magnetic beads. Alternatively, when using the standard curve method of analysis, an appropriate amount of Dynabeads magnetic beads can be added to each sample used to construct the standard curve.
20 beta-hydroxysteroid dehydrogenase and CYP19A1 are differentially expressed during maturation in Atlantic cod (Gadus morhua).
Authors:Mittelholzer C, Andersson E, Consten D, Hirai T, Nagahama Y, Norberg B,
Journal:J Mol Endocrinol
PubMed ID:17909270
In order to better quantify the molecular mechanisms regulating final oocyte maturation and spawning, complete coding sequences with partially or fully untranslated regions for the steroidogenic enzymes, cytochrome P450 aromatase and 20 beta-hydroxysteroid dehydrogenase, were cloned from ovaries of Atlantic cod (Gadus morhua). The nucleotide and amino acid sequences showed ... More