earticle

영어

Targeting particular mRNAs has become an excellent approach for gene silencing. Here, we showed a cell-penetrating antibody (transbody) that specifically hydrolyzes targeted mRNAs in the cellular cytosol and leads to targeted gene silencing. We generated a synthetic library on the yeast surface based on 3D8 VL, which is a cell-penetrating and nucleic acid-hydrolyzing single domain antibody of the light chain variable domain. With the cell-penetrating activity, 3D8 VL into he cytosol of living cells can selectively decrease the amount of target sequence-carrying mRNAs. We selected 3D8 VL variants had higher affinity and greater selective hydrolyzing activity for target single-stranded (ss)-DNAs than for off targets in the library by using 18bp-ssDNAs as target substrates. In particular, one 3D8 VL variant targeting the Her2 sequence showed more efficient downregulation of Her2 expression than a smallinterfering RNA targeting the same sequence, and the variant caused apoptotic cell death of Her2-overexpressing breast cancer cells. Our results demonstrate that the 3D8 VL variants with cell penetrating, nucleic acid-hydrolyzing activity and sequence-selectivity could degrade target mRNAs in the cytosol,
which suggests that they would be potential tools in anti-cancer or anti-viral therapies.