The influence of matrix attachment regions on transgene expression in Arabidopsis thaliana wild type and gene silencing mutants.

Many studies in both animal and plant systems have shown that matrix attachment regions (MARs) can increase the expression of flanking transgenes. However, our previous studies revealed no effect of the chicken lysozyme MARs (chiMARs) on transgene expression in the first generation transgenic Arabidopsis thaliana plants transformed with a beta-glucuronidase gene (uidA) unless gene silencing mutants were used as genetic background for transformation. In the present study, we investigated why chiMARs do not influence transgene expression in transgenic wild-type Arabidopsis plants.

Stable high-level transgene expression in Arabidopsis thaliana using gene silencing mutants and matrix attachment regions.

Basic and applied research involving transgenic plants often requires consistent high-level expression of transgenes. However, high inter-transformant variability of transgene expression caused by various phenomena, including gene silencing, is frequently observed. Here, we show that stable, high-level transgene expression is obtained using Arabidopsis thaliana post-transcriptional gene silencing (PTGS) sgs2 and sgs3 mutants.

A set of modular plant transformation vectors allowing flexible insertion of up to six expression units.

We have constructed a binary vector for Agrobacterium-mediated plant transformation, which has a multiple cloning site consisting of 13 hexanucleotide restriction sites, 6 octanucleotide restriction sites and 5 homing endonuclease sites. The homing endonuclease sites have the advantages to be extremely rare in natural sequences and to allow unidirectional cloning. We have also constructed a set of auxiliary vectors allowing the assembly of expression cassettes flanked by homing endonuclease sites.