Capillary electrophoresis of RNA in hydroxyethylcellulose polymer with various molecular weights

• We separated the long RNA in hydroxyethylcellulose (HEC) by capillary electrophoresis.
• The separation performance of RNA was researched by varying the molecular weight of HEC.
• The migration mechanisms for the long RNA in HEC with different molecular weight were summarized.

Recent research demonstrates that large numbers of long noncoding RNAs (lncRNAs) in mammals exhibit indices of functionality, and thus analysis of longer RNAs is of great significance. In the present work, we investigated the effect of molecular weight on the separation performance of long RNA by capillary electrophoresis (CE). Results demonstrate that (1) low molecular weight of hydroxyethylcellulose (HEC) (90k) favors the separation of short RNA (<1000 nt). The resolution for short RNA was improved and the migration time was linearly extended with the increase of polymer concentration. (2) In the longer chain HEC (250k, 720k and 1300k), the resolution for the small RNA fragment (<1000 nt) became better as the polymer concentration increased, whereas the resolution for the large ones (>3000 nt) deteriorated. (3) Based on logarithmic plot, there exist two migration regimes for RNA in short chain HEC (90k), three regimes in moderate chain HEC (250k and 720k), and four regimes in the long chain HEC (1300k). Such a systematic investigation of long RNAs may be useful for research on lncRNAs in the length range of 100–10,000 nt.