van Lin L H, Pace T, Janse C J, Birago C, Ramesar J, Picci L, Ponzi M, Waters A P
Department of Parasitology, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.
Nucleic Acids Res. 2001 May 15;29(10):2059-68. doi: 10.1093/nar/29.10.2059.
A 13.6 kb contig of chromosome 5 of Plasmodium berghei, a rodent malaria parasite, has been sequenced and analysed for its coding potential. Assembly and comparison of this genomic locus with the orthologous locus on chromosome 10 of the human malaria Plasmodium falciparum revealed an unexpectedly high level of conservation of the gene organisation and complexity, only partially predicted by current gene-finder algorithms. Adjacent putative genes, transcribed from complementary strands, overlap in their untranslated regions, introns and exons, resulting in a tight clustering of both regulatory and coding sequences, which is unprecedented for genome organisation of PLASMODIUM: In total, six putative genes were identified, three of which are transcribed in gametocytes, the precursor cells of gametes. At least in the case of two multiple exon genes, alternative splicing and alternative transcription initiation sites contribute to a flexible use of the dense information content of this locus. The data of the small sample presented here indicate the value of a comparative approach for Plasmodium to elucidate structure, organisation and gene content of complex genomic loci and emphasise the need to integrate biological data of all Plasmodium species into the P.falciparum genome database and associated projects such as PlasmodB to further improve their annotation.
已对啮齿动物疟原虫伯氏疟原虫5号染色体上一个13.6 kb的重叠群进行了测序，并分析了其编码潜力。将该基因组位点与人类疟原虫恶性疟原虫10号染色体上的直系同源位点进行组装和比较，结果显示基因组织和复杂性的保守程度出乎意料地高，而当前的基因预测算法仅部分预测到了这一点。从互补链转录的相邻推定基因在其非翻译区、内含子和外显子中重叠，导致调控序列和编码序列紧密聚集，这在疟原虫的基因组组织中是前所未有的：总共鉴定出六个推定基因，其中三个在配子体（配子的前体细胞）中转录。至少在两个多外显子基因的情况下，可变剪接和可变转录起始位点有助于灵活利用该位点的密集信息内容。本文给出的小样本数据表明，比较方法对于疟原虫阐明复杂基因组位点的结构、组织和基因含量具有价值，并强调需要将所有疟原虫物种的生物学数据整合到恶性疟原虫基因组数据库以及诸如PlasmodB等相关项目中，以进一步改进它们的注释。
