(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 2. Different uses of antisense morpholino oligonucleotides. (A)
Inhibition of translation by an antisense morpholino oligonucleotide. The MO
is targeted to sequence 5' of the translation start site and inhibits
progression of the initiation complex. (B-E) Use of MOs to prevent
correct splicing of X. tropicalis NRH1. (B) The first three exons of
NRH1. Arrows indicate the positions of the forward (F1)
and reverse (R1, R2) PCR primers used to test the
efficacy of the splicing MOs. Exon 1 is 326 bp, intron 1 is 9013 bp, exon 2 is
134 bp, intron 2 is 740 bp, and exon 3 is 363 bp. If the mRNA is correctly
spliced, the combination of F1 and R1 should yield no
PCR product and F1 and R2 should give a product of 490
bp. (C) The +intron1 MO is designed to cause intron 1 to be retained. This
would result in the first 15 amino acids of NRH1 being followed by 67 missense
amino acids before a stop codon is reached. If intron 1 is retained in this
way, the combination of F1 and R1 should give a PCR
product of 280 bp, and F1 and R2 should yield a product
in excess of 9.0 kb. (D) The
exon2 MO is designed to exclude exon 2
from the mature RNA. In this case, exon 3 would no longer be in frame with
exon 1, and a truncated protein consisting of 15 correct amino acids followed
by 25 missense residues would be formed before a stop codon is encountered.
Deletion of exon 2 in this way should cause the combination of F1
and R1 to yield no PCR product, and F1 and R2
should yield a product of 360 bp. (E) Verification of the efficacy of MOs
+intron1 and
exon2. Comparisons of lane 2 with lane 3, and lane 6 with
lane 7, indicate that both MOs reduce levels of correctly spliced transcript
by
50%. Note that the predicted 9.5 kb band in lane 4 is absent, probably
because the PCR conditions do not efficiently amplify products of this size.
(F) Activation of a caged morpholino. An inhibitory oligonucleotide is
coupled to a specific MO through a photocleavable linker. Irradiation [10
seconds of 360 nm light (h
)] cleaves the linker and allows the MO to exert
its effects. B-D are redrawn, and E is reproduced, with permission, from Knapp
et al. (Knapp et al., 2006). F
is redrawn, with permission, from Shestopalov et al.
(Shestopalov et al.,
2007).