[The potential role of nuclear matrix attachment regions (MARs) in regulation of gene expression].
Gene transfer technology is being used to enhance agronomic performance or improve quality traits in a wide variety of crop species. However, it is sometimes severely handicapped by difficulty in obtaining material in which transgene expression is predictable and stable over many generations. Because integration seemed to occur randomly in the plant genome, it was thought that some transgenes would be integrated in a relatively uncondensed, transcriptionally active chromatin environment, while others in a condensed, transcriptionally inert chromatin structure. Nuclear matrix attachment regions (MARs) are defined as DNA sequences that bind preferentially to the proteins of the nuclear matrix. They typically are localized at the borders of gene domains, implicating them in the formation of individual loops of higher order chromatin structure and transcription regulation. When MARs are positioned on either side of a transgene their presence usually results in higher and more stable espression in transgenic plants, most likely by minimizing gene silencing. In this review, we focus mainly on novel findings and our observations concerning the function of MARs in transcription regulation. Our objective is not only to summarize the current data and present several possible models to explain MAR effects on the transcription regulation, but also to point out some open questions involving the utilization of MARs in constructing high efficient expression vectors.
Zhang
Ke-Wei
KW
College of Life Sciences, Shandong Agricultural University, Taian 271018, China.
Wang
Jian-Mei
JM
Zheng
Cheng-Chao
CC
D002843:Chromatin / Q000502:physiology; D004247:DNA / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008957:Models, Genetic; D015530:Nuclear Matrix / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D019076:Transgenes / Q000235:genetics
D002843:Chromatin; D009687:Nuclear Proteins; D004247:DNA