New England Biolabs offers several products for isolation of RNA.
Oligo (dT)25 Cellulose or Magnetic beads (NEB #S1408, NEB #S1419) and the polyA Spin mRNA Isolation Kit exploit the polyA tail on cytoplasmic or "total" RNA isolated from eukaryotic tissue and cells for the isolation of mRNA.
The Magnetic mRNA Isolation Kit (NEB #S1550) is designed to isolate intact poly(A)+ RNA from cells and tissue without requiring phenol or other organic solvents.
The p19 siRNA Binding Protein (NEB #M0310) (19 kDa) from the Carnation Italian Ringspot Virus (CIRV) plant binds siRNAs with nanomolar affinity (1). The dimeric protein binds 21 base siRNAs with a 2 base 3´ extension and a 5´phosphate. The protein binds RNA in a size dependent and sequence independent manner. If the siRNAs are 4 bases longer, the affinity for the protein is reduced about 100-fold (2). When p19 siRNA Binding Protein is expressed in plants, it suppresses RNA interference (3).
(1) Silhavy, D. et al. (2002) EMBO J., 21, 3070-3080. PMID: 12065420
(2) Vargason, J.M., et al. (2003) Cell, 115, 799-811. PMID: 14697199
(3) Qiu, W. et al. (2002) Mol. Plant Microbe Interact, 15, 269-280. PMID: 11952130