RNA Isolation – Colleens’ Sea Star Coelomycetes Samples

Isolated RNA from the following samples stored in RNAlater:

  • TH52 3.28.14 c-fluid
  • TH54 3.28.14 c-fluid
  • CH55 3.28.14 c-fluid
  • CH56 3.28.14 c-fluid
  • CH57 3.28.14 c-fluid
  • TH65 3.28.14 c-fluid
  • TH66 3.28.14 c-fluid
  • TH67 3.28.14 c-fluid

Spun samples 5000g, 20mins @ RT to pellet any cells. Discarded supe. Resuspended cells/debris in 1mL TriReagent. Disrupted cells by pipetting and vortexting. RNA was isolated using the Direct-zol RNA Miniprep Kit (ZymoResearch). RNA was DNase treated on-column, as described in the manufacturer’s protocol, using DNase I. RNA was eluted from the columns using 25uL of nuclease-free H2O and spec’d on a NanoDrop1000.


So, this is disheartening. Overall, the RNA looks pretty crappy; poor 260/280 ratios and a general shift in absorbance to 270nm. Plus, the yields aren’t that great. Maybe RNA left on the column and/or some sort of contaminant pushing these readings out of whack?

I will perform another elution on the columns with 50uL of nuclease-free H2O and spec that elution set:

There’s still a shift in the peak absorbance in most samples to 270nm… I’m going to combine the two sets of elutions and spec:

Although the 260/280 values are significantly better, there’s still this persistent shift of peak absorbance to 270nm. I contacted technical support for the kit and they say the absorbance shift is indicative of phenol contamination. They have advised that I add a volume of TriReagent to the RNA and re-run it through a new set of columns, following the entire RNA isolation protocol.

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