Wu Jianzhong, Mizuno Hiroshi, Hayashi-Tsugane Mika, Ito Yukiyo, Chiden Yoshino, Fujisawa Masaki, Katagiri Satoshi, Saji Shoko, Yoshiki Shoji, Karasawa Wataru, Yoshihara Rie, Hayashi Akiko, Kobayashi Harumi, Ito Kazue, Hamada Masao, Okamoto Masako, Ikeno Maiko, Ichikawa Yoko, Katayose Yuichi, Yano Masahiro, Matsumoto Takashi, Sasaki Takuji
Rice Genome Research Program (RGP), National Institute of Agrobiological Sciences/Institute of the Society for Techno-innovation of Agriculture, Forestry and Fisheries, Tsukuba, Ibaraki 305-8602, Japan.
Plant J. 2003 Dec;36(5):720-30. doi: 10.1046/j.1365-313x.2003.01903.x.
We constructed physical maps of rice chromosomes 1, 2, and 6-9 with P1-derived artificial chromosome (PAC) and bacterial artificial chromosome (BAC) clones. These maps, with only 20 gaps, cover more than 97% of the predicted length of the six chromosomes. We submitted a total of 193 Mbp of non-overlapping sequences to public databases. We analyzed the DNA sequences of 1316 genetic markers and six centromere-specific repeats to facilitate characterization of chromosomal recombination frequency and of the genomic composition and structure of the centromeric regions. We found marked changes in the relative recombination rate along the length of each chromosome. Chromosomal recombination at the centromere core and surrounding regions on the six chromosomes was completely suppressed. These regions have a total physical length of about 23 Mbp, corresponding to 11.4% of the entire size of the six chromosomes. Chromosome 6 has the longest quiescent region, with about 5.6 Mbp, followed by chromosome 8, with quiescent region about half this size. Repetitive sequences accounted for at least 40% of the total genomic sequence on the partly sequenced centromeric region of chromosome 1. Rice CentO satellite DNA is arrayed in clusters and is closely associated with the presence of Centromeric Retrotransposon of Rice (CRR)- and RIce RetroElement 7 (RIRE7)-like retroelement sequences. We also detected relatively small coldspot regions outside the centromeric region; their repetitive content and gene density were similar to those of regions with normal recombination rates. Sequence analysis of these regions suggests that either the amount or the organization patterns of repetitive sequences may play a role in the inactivation of recombination.
我们利用P1衍生人工染色体（PAC）和细菌人工染色体（BAC）克隆构建了水稻第1、2、6至9号染色体的物理图谱。这些图谱仅有20个缺口，覆盖了这6条染色体预测长度的97%以上。我们总共向公共数据库提交了193兆碱基对的非重叠序列。我们分析了1316个遗传标记和6个着丝粒特异性重复序列的DNA序列，以促进对染色体重组频率以及着丝粒区域的基因组组成和结构的表征。我们发现每条染色体长度上的相对重组率有显著变化。这6条染色体着丝粒核心及周边区域的染色体重组完全受到抑制。这些区域的总物理长度约为23兆碱基对，相当于这6条染色体总大小的11.4%。第6号染色体的静止区域最长，约为5.6兆碱基对，其次是第8号染色体，其静止区域约为第6号染色体静止区域大小的一半。在部分测序的第1号染色体着丝粒区域，重复序列占基因组总序列的至少40%。水稻CentO卫星DNA成簇排列，并且与水稻着丝粒反转录转座子（CRR）和水稻反转录元件7（RIRE7）样反转录元件序列的存在密切相关。我们还在着丝粒区域之外检测到相对较小的冷点区域；它们的重复序列含量和基因密度与正常重组率区域相似。对这些区域的序列分析表明，重复序列的数量或组织模式可能在重组失活中起作用。
