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Matrix attachment regions increase transgene expression levels and stability in transgenic rice plants and their progeny
Author(s) -
Vain Philippe,
Worland Barbara,
Kohli Ajay,
Snape John W.,
Christou Paul,
Allen George C.,
Thompson William F.
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00446.x
Subject(s) - transgene , mars exploration program , scaffold/matrix attachment region , biology , callus , population , genetically modified rice , genetically modified crops , genetically modified organism , microbiology and biotechnology , genetics , gene expression , gene , astrobiology , demography , sociology , chromatin remodeling
Summary To investigate the effect of matrix attachment regions (MARs) on transgene expression levels and stability in cereal crops, we generated 83 independent transgenic rice callus lines containing a gusA expression cassette either as a simple expression unit, or flanked with MARs from tobacco (Rb7) or yeast (ARS1). Transgenic rice plants were regenerated from these callus lines and analysed at the structural and expression levels over two generations. In the first generation (T 0 ), both Rb7 and ARS1 MARs significantly increased transgene expression levels. In the populations of plants containing MARs, we observed a significant reduction in the number of non‐expressing lines compared to the population of plants without MARs. However, variation in β‐glucuronidase (GUS) expression levels between independent lines was similar both in the presence and absence of flanking MARs. In the presence of MARs, GUS activity increased in proportion to transgene copy number up to 20 copies, but was generally reduced in lines carrying a higher copy number. In the population of plants without MARs, there was no correlation between expression level and transgene copy number. In the second generation (T 1 ), transgene expression levels were significantly correlated with those of the T 0 parents. The Rb7 MARs significantly improved the stability of transgene expression levels over two generations, and therefore appear to offer protection against transgene silencing. Our study shows that the exploitation of MARs may be an important strategy for stabilising transgene expression levels in genetically engineered cereals.