shRNA
shRNA (short hairpin RNA) is a DNA molecule that can be
cloned into expression vectors to express siRNA (19-21nt RNA duplex) for RNAi
interference studies. shRNA has the following structural
features:
·
A short nucleotide
sequence ranging from 19-29 nucleotides derived from the target gene, followed
by
·
A short spacer of 4-15
nucleotides (i.e. loop) and
·
A 19-29 nucleotide
sequence that is the reverse complement of the initial target
sequence
Invitrogen offers shRNA design (BLOCK-iT™ RNAi Designer) and
synthesis services (Custom Primer
Resources) and vectors for shRNA expression. Use BLOCK-iT(TM) Inducible H1
RNAi Entry Vector Kit for inducible shRNA expression and BLOCK-iT™
U6 Entry Vector kit for constitutive expression.
shRNA Design
The BLOCK-iT™ RNAi Designer finds 21 nt gene-specific
target sequences that fulfill proprietary design criteria and reports up to 10
top scoring target sequences.
For the selected target sequences, the
designer:
·
Uses selected default or
entered custom loop sequence
·
Uses appropriate linker
sequences for directional cloning into Invitrogen's BLOCK-iTTM entry
vector (pENTRTM/U6) vector or BLOCK-iT™ H1/TO vector
·
Designs top and bottom
strands of the shRNA oligo, incorporating linker, target, loop and reverse
complement of the target sequence.
·
Reports top strand, bottom
strand and the annealed oligo sequence
See Online Help for
additional information.
Order both top and bottom DNA
strands from Invitrogen Custom
Primer Services and anneal both strands to generate a double-stranded oligo
with 4-nucleotide overhangs suitable for directional cloning into Invitrogen's
vectors. Check shRNA annealing protocol for annealing the ss DNA
oligo.