Functional cell permeable motifs within medically relevant proteins.

Increasing experimental evidence indicates that short polybasic peptides are able to translocate across the membrane of living cells. However, these peptides, often derived from viruses and insects, may induce unspecific effects that could mask the action of their cargoes. Here, we show that a panel of lysine and/or arginine-rich peptides, derived from human proteins involved in cell signalling pathways leading to inflammation, possess the intrinsic ability to cross intact cellular membranes.

Suppression of gene expression by a cell-permeable Tet repressor.

Engineered transcription factors designed to selectively activate or repress endogenous genes have great potential in medical and biotechnological applications. Ultimately, their success will depend on the development of efficient delivery systems. We show here that a chimeric tetracycline- controlled transcription factor, encompassing the Tet repressor (TetR) from the tetracycline-resistance operon (tet from Escherichia coli transposon Tn10) and a cell membrane transducing peptide, is able to regulate transcription from a tetracycline responsive promoter (pCMV2xtetO2).

A recombinant H1 histone-based system for efficient delivery of nucleic acids.

We describe here a unique transfer system based on a truncated form of the human linker histone H1F4 for the delivery of nucleic acids to a variety of cells. The efficiency of truncated histone H1.4F was assessed using both primary mammalian and immortalised insect and mammalian cell lines.