Serum stability
To increase stability, we incorporated LNA (locked nucleic
acid)-modifications to the 3’ ends of the siR-7 guide and passenger
strands. The LNA-modified siR-7-EM (siLNA) was synthesized by
“DNA-technology” company (Moscow, Russia).
Duplexes of siRNA (siR-7) and siLNA (siR-7-EM) (3 μg) were incubated at
37°C in 50% fetal bovine serum (Invitrogen) diluted in phosphate
buffered saline for 264 h. Aliquots of 10 μg were withdrawn at indicated
time points and stored at -20°C. Samples were then subjected to
electrophoresis in 1.5% agarose gel, stained with Ethidium Bromide and
quantified by Imagequant software (Amersham Biosciences, Uppsala,
Sweden).