Plant Science

Suppressing Silencing

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Science  04 Oct 2002:
Vol. 298, Issue 5591, pp. 15-17
DOI: 10.1126/science.298.5591.15e

Gene expression is regulated not only by the swarm of transcription factors that interact with the promoter region of the gene but also by the nuclear localization of the gene. Matrix attachment regions (MARs) of DNA bind to the proteinaceous network of the nucleus and segregate chromosomal subdomains; the MARs may define loops of chromatin presenting multiple genes for coordinated activation or repression by soluble factors. In plants, the loops seem to be on the order of 10 kilobases in length. Surveying variability in expression from low-copy-number transgenes in maize, Brouwer et al. find that different MARs have diverse effects on gene expression, in some cases reducing transgene silencing, and an individual MAR could have multiple effects according to the developmental status of the cells being tested. The MARs offer a glimpse into a complex process, which can alter both chromatin structure and gene expression. — PJH

Plant Cell14, 2251 (2002).

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