Post-transcriptional gene-silencing and RNA interference: genetic immunity, mechanisms and applications

Abstract

This review summarises the development of our understanding of co-suppression in plants, and describes how co-suppression relates to similar post-transcriptional gene-silencing (PTGS) phenomena, and underlying genetic immunity mechanisms. These comparisons have enabled us to develop sophisticated models that go some way to explaining what causes co-suppression, and indicate that manipulation of the underlying mechanisms can provide the plant biotechnologist with new tools to control gene expression and silencing in transgenic plants. Recently, it has become apparent that the mechanism underlying PTGS has, at least in essence, been conserved through divergent evolution and similar mechanisms to co-suppression are functional in nematode, insect and mammalian cells. In addition to the original applications in plant biotechnology, the development of technology based on PTGS is proving to be a highly valuable alternative to mutagenesis for functional genomics applications in both plant and animal model species. The recent discovery that PTGS mechanisms operate in mammalian cells indicates that there are likely to be wider applications for technology based on PTGS, possibly including human therapeutics.

A challenge for 21st century molecular biology and biochemistry: what are the causes of obligate autotrophy and methanotrophy?

“…The reason for the failure of N. europaea and M. capsulatus to synthesize functional α‐ketoglutarate dehydrogenase and the significance of this to their obligate physiologies remain to be established. Among the possibilities are: (i) failure to transcribe one or both of the genes into mRNA, (ii) deletion of regulatory parts of the operons, (iii) that the obligate nature of their central metabolism results from regulatory controls causing permanent repression of the genes, or (iv) some kind of post‐transcriptional gene silencing, possibly by endogenous small interfering RNAs [17,131].…”

Potential Use of Transgenic Plums Resistant to Plum Pox Virus Field Infection

“…Using plum (Prunus domestica L.) as a model, we have shown that through genetic transformation, stone fruits highly resistant to PPV can be developed (Scorza et al, 1994;Ravelonandro et al, 1997). This resistance is based on post-transcriptional gene silencing (PTGS) (Turner and Schuch, 2000) induced by the PPV coat protein transgene that was inserted into plum 120 (Scorza et al, 2001). In the current report we describe field tests developed in order to evaluate resistance to natural aphid vectored infection.…”