Borisjuk N V, Davidjuk Y M, Kostishin S S, Miroshnichenco G P, Velasco R, Hemleben V, Volkov R A
Institut für Pflanzengenetik und Kulturpflanzenforschung, Gatersleben, Germany.
Plant Mol Biol. 1997 Nov;35(5):655-60. doi: 10.1023/a:1005856618898.
The nucleotide sequence of the intergenic spacer (IGS) region between the 25S and the 18S rRNA coding regions has been determined for tobacco (Nicotiana tabacum). The IGS (5140 bp in length) can be subdivided into several regions (I-VII) two of which, upstream and downstream of the putative transcription initiation site (TIS), contain prominent subrepeats (A and C). The unique sequence in the central part of the IGS (region IV) preceding the TIS is extremely AT-rich. The distance from the putative TIS to the 5' end of the 18S rRNA gene is 3005 bp. The IGS sequences are compared with potato (Solanum tuberosum) and tomato (Lycopersicon esculentum) IGS. Restriction mapping of 13 Nicotiana species shows that considerable rDNA repeat length heterogeneity in this genus is probably due to different numbers of A and C subrepeats.
已确定烟草（Nicotiana tabacum）25S和18S rRNA编码区之间基因间隔区（IGS）的核苷酸序列。IGS（长度为5140 bp）可细分为几个区域（I - VII），其中两个区域，即假定转录起始位点（TIS）的上游和下游，包含显著的亚重复序列（A和C）。TIS之前IGS中部（区域IV）的独特序列富含AT。从假定的TIS到18S rRNA基因5'端的距离为3005 bp。将IGS序列与马铃薯（Solanum tuberosum）和番茄（Lycopersicon esculentum）的IGS进行比较。对13种烟草属物种的限制性图谱分析表明，该属中相当大的rDNA重复长度异质性可能是由于A和C亚重复序列数量不同所致。
