Zhou Cong-Zhao, Confalonieri Fabrice, Esnault Catherine, Zivanovic Yvan, Jacquet Michel, Janin Joel, Perasso Roland, Li Zhen-Gang, Duguet Michel
Institut de Génétique et Microbiologie, Université Paris-Sud et CNRS, 91405 Orsay, France.
Gene. 2003 Jul 17;312:189-95. doi: 10.1016/s0378-1119(03)00616-4.
We sequenced an 80 kb DNA region containing the complete sequence of the silkworm Bombyx mori fibroin gene and its flanking, especially the upstream, regions (-62 kb). About 30% of the 62 kb upstream region is composed of repetitive elements including short interspersed elements Bm1, long interspersed elements L1Bm and mariner-like elements Bmmar1 which are widespread over the silkworm genome. This 62 kb region is also enriched of commonly considered matrix association region (MAR) motifs. A total of 25 individual MAR recognition signatures (MRSs) were identified, with 24 at the upstream and one at the downstream region. Combining two newly developed MAR prediction programs (MAR-finder and Chrclass), ten candidate MARs were predicted, with five containing MRS and seven related to the repetitive elements. The wide distribution of nested repetitive elements, candidate MARs, DNase I hypersensitive sites and other potential regulatory factors recognition sites indicates this region is probably a unique huge cis-acting element contributing to the regulation of the spatial and temporal specificity and efficiency of fibroin gene expression.
