Benitec, Promega launch new RNAi products

Brisbane-based gene technology company Benitec (ASX:BLT) today launched the first commercial gene-silencing vectors to emerge from its global licensing agreement signed with the US-based Promega Corporation in Madison, Wisconsin, in April last year.

Promega's new Sistrike vectors provide medical researchers with a plug-and-play vehicle for inactivating target genes in mammalian cells.

The Sistrike vectors exploit Benitec's proprietary DNA-directed RNA interference (ddRNAi) technology.

The linearised vectors are designed to rapidly and easily accept cloned nucleotides from genes that researchers wish to silence -- ddRNAi allows for prolonged silencing of genes in human cell lines, where transfection with synthetic interfering RNAs (siRNAs) provides only transient silencing -- typically in the range of 48 to 72 hours.

A selectable marker gene incorporated in the construct confers resistance to the antibiotic tetracycline, so researchers can readily identify transformed cells.

Benitec's director of research and technology, Dr Ken Reed, said the Sistrike vectors could also accommodate externally inducible promoters.

Reed said that Benitec and Promega would spend the next few months concentrating on developing gene-silencing vectors with in-built tissue-specific promoters, and externally induced promoters that will allow researchers to silence a target gene at any time, or in any tissue.

These would include constructs that will allow researchers to delay silencing of target genes in transgenic animals until infancy or maturity, in cases where silencing during embryonic development would prove lethal. Tissue-specific promoters will allow researchers to silence target genes only in particular tissues or organs in 'knockout' animals.

Reed said the partner companies would be focusing on increasingly specialised gene-silencing products for research, designed for maximum convenience and flexibility of use.