An ancient spliceosomal intron in the ribosomal protein L7a gene (Rpl7a) of Giardia lamblia.
An ancient spliceosomal intron in the ribosomal protein L7a gene (Rpl7a) of Giardia lamblia.
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DOI：
10.1186/1471-2148-5-45
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发表时间：
2005-08-18
影响因子：
3.4
通讯作者：
Gray MW
中科院分区：
文献类型：
--
作者：
Russell AG;Shutt TE;Watkins RF;Gray MW
以前在单细胞真核寄生虫贾第鞭毛虫（一种寄生虫）中只发现了一个剪接体型内含子。该内含子长度仅为35个核苷酸，并且具有非典型的5'内含子边界序列CT而不是GT。在核糖体蛋白L7a基因（Rp17a）中，具有典型的GT 5'内含子边界序列。两个已知的贾第虫内含子序列的比较揭示了在5'和3'内含子边界处的广泛的核苷酸同一性，类似于最近在迷走毛滴虫（一种副基原虫）中的剪接体型内含子边界处鉴定的保守序列基序。在此基础上，我们搜索了部分G。Lamblia基因组序列的这些保守特征，并确定了第三剪接体内含子，在一个未分配的开放阅读框架。我们对其他真核生物中Rpl7a内含子的综合分析表明，它在进化上是保守的，是一个古老的真核生物内含子。Rpl7a内含子的系统发育分布和特性的分析表明其作为系统发育标记物来评估特定真核生物分组的效用。此外，对G. Lamblia内含子的研究为进一步了解最近在相关生物体中发现的剪接体内含子所具有的一些保守和独特的特征提供了新的视角。迷走神经和Carpediemonasmembranifera。
Only one spliceosomal-type intron has previously been identified in the unicellular eukaryotic parasite, Giardia lamblia (a diplomonad). This intron is only 35 nucleotides in length and is unusual in possessing a non-canonical 5' intron boundary sequence, CT, instead of GT. We have identified a second spliceosomal-type intron in G. lamblia, in the ribosomal protein L7a gene (Rpl7a), that possesses a canonical GT 5' intron boundary sequence. A comparison of the two known Giardia intron sequences revealed extensive nucleotide identity at both the 5' and 3' intron boundaries, similar to the conserved sequence motifs recently identified at the boundaries of spliceosomal-type introns in Trichomonas vaginalis (a parabasalid). Based on these observations, we searched the partial G. lamblia genome sequence for these conserved features and identified a third spliceosomal intron, in an unassigned open reading frame. Our comprehensive analysis of the Rpl7a intron in other eukaryotic taxa demonstrates that it is evolutionarily conserved and is an ancient eukaryotic intron. An analysis of the phylogenetic distribution and properties of the Rpl7a intron suggests its utility as a phylogenetic marker to evaluate particular eukaryotic groupings. Additionally, analysis of the G. lamblia introns has provided further insight into some of the conserved and unique features possessed by the recently identified spliceosomal introns in related organisms such as T. vaginalis and Carpediemonas membranifera.
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DOI：
10.1073/pnas.0408274102
发表时间：
2005-01-18
影响因子：
11.1
作者：
Roy, SW;Gilbert, W
通讯作者：
Gilbert, W
DOI：
10.1073/pnas.042700299
发表时间：
2002-03-19
影响因子：
11.1
作者：
Nixon, JEJ;Wang, A;Samuelson, J
通讯作者：
Samuelson, J
影响因子：
10.7
作者：
Fahrni, JF;Bolivar, I;Pawlowski, J
通讯作者：
Pawlowski, J
DOI：
10.1099/00207713-52-2-297
发表时间：
2002-03-01
影响因子：
2.8
作者：
Cavalier-Smith, T
通讯作者：
Cavalier-Smith, T
DOI：
10.1099/ijs.0.02578-0
发表时间：
2003-11-01
影响因子：
2.8
作者：
Simpson, AGB
通讯作者：
Simpson, AGB