@article{pascuzzi_flores-vergara_lee_sosinski_vaughn_hanley-bowdoin_thompson_allen_2014, title={In Vivo Mapping of Arabidopsis Scaffold/Matrix Attachment Regions Reveals Link to Nucleosome-Disfavoring Poly(dA:dT) Tracts}, volume={26}, ISSN={["1532-298X"]}, DOI={10.1105/tpc.113.121194}, abstractNote={This work uses tiling microarrays to map S/MARs on Arabidopsis chromosome 4. S/MARs were found to be spaced more closely than in the large plant and animal genomes studied to date and preferentially enriched in poly(dA:dT) tracts, sequences that resist nucleosome formation. Most S/MARs occur near gene transcription start sites, and these genes show an increased probability of expression. Scaffold or matrix attachment regions (S/MARs) are found in all eukaryotes. The pattern of distribution and genomic context of S/MARs is thought to be important for processes such as chromatin organization and modulation of gene expression. Despite the importance of such processes, much is unknown about the large-scale distribution and sequence content of S/MARs in vivo. Here, we report the use of tiling microarrays to map 1358 S/MARs on Arabidopsis thaliana chromosome 4 (chr4). S/MARs occur throughout chr4, spaced much more closely than in the large plant and animal genomes that have been studied to date. Arabidopsis S/MARs can be divided into five clusters based on their association with other genomic features, suggesting a diversity of functions. While some Arabidopsis S/MARs may define structural domains, most occur near the transcription start sites of genes. Genes associated with these S/MARs have an increased probability of expression, which is particularly pronounced in the case of transcription factor genes. Analysis of sequence motifs and 6-mer enrichment patterns show that S/MARs are preferentially enriched in poly(dA:dT) tracts, sequences that resist nucleosome formation, and the majority of S/MARs contain at least one nucleosome-depleted region. This global view of S/MARs provides a framework to begin evaluating genome-scale models for S/MAR function.}, number={1}, journal={PLANT CELL}, author={Pascuzzi, Pete E. and Flores-Vergara, Miguel A. and Lee, Tae-Jin and Sosinski, Bryon and Vaughn, Matthew W. and Hanley-Bowdoin, Linda and Thompson, William F. and Allen, George C.}, year={2014}, month={Jan}, pages={102–120} }
 @article{lee_pascuzzi_settlage_shultz_tanurdzic_rabinowicz_menges_zheng_main_murray_et al._2010, title={Arabidopsis thaliana Chromosome 4 Replicates in Two Phases That Correlate with Chromatin State}, volume={6}, ISSN={1553-7404}, url={http://dx.doi.org/10.1371/journal.pgen.1000982}, DOI={10.1371/journal.pgen.1000982}, abstractNote={DNA replication programs have been studied extensively in yeast and animal systems, where they have been shown to correlate with gene expression and certain epigenetic modifications. Despite the conservation of core DNA replication proteins, little is known about replication programs in plants. We used flow cytometry and tiling microarrays to profile DNA replication of Arabidopsis thaliana chromosome 4 (chr4) during early, mid, and late S phase. Replication profiles for early and mid S phase were similar and encompassed the majority of the euchromatin. Late S phase exhibited a distinctly different profile that includes the remaining euchromatin and essentially all of the heterochromatin. Termination zones were consistent between experiments, allowing us to define 163 putative replicons on chr4 that clustered into larger domains of predominately early or late replication. Early-replicating sequences, especially the initiation zones of early replicons, displayed a pattern of epigenetic modifications specifying an open chromatin conformation. Late replicons, and the termination zones of early replicons, showed an opposite pattern. Histone H3 acetylated on lysine 56 (H3K56ac) was enriched in early replicons, as well as the initiation zones of both early and late replicons. H3K56ac was also associated with expressed genes, but this effect was local whereas replication time correlated with H3K56ac over broad regions. The similarity of the replication profiles for early and mid S phase cells indicates that replication origin activation in euchromatin is stochastic. Replicon organization in Arabidopsis is strongly influenced by epigenetic modifications to histones and DNA. The domain organization of Arabidopsis is more similar to that in Drosophila than that in mammals, which may reflect genome size and complexity. The distinct patterns of association of H3K56ac with gene expression and early replication provide evidence that H3K56ac may be associated with initiation zones and replication origins.}, number={6}, journal={PLoS Genetics}, publisher={Public Library of Science (PLoS)}, author={Lee, Tae-Jin and Pascuzzi, Pete E. and Settlage, Sharon B. and Shultz, Randall W. and Tanurdzic, Milos and Rabinowicz, Pablo D. and Menges, Margit and Zheng, Ping and Main, Dorrie and Murray, James A. H. and et al.}, editor={Copenhaver, Gregory P.Editor}, year={2010}, month={Jun}, pages={e1000982} }