Spliced leader RNA and 5S rRNA genes in Herpetomonas spp. are genetically linked.
Spliced leader RNA and 5S rRNA genes in Herpetomonas spp. are genetically linked.
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疱疹单胞菌中剪接的前导 RNA 和 5S rRNA 基因。
DOI：
10.1093/nar/20.4.913
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发表时间：
1992
影响因子：
14.9
通讯作者：
Aksoy,S
中科院分区：
文献类型：
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作者：
Aksoy,S
在锥虫科，成熟信息的5‘端含有一个保守的核苷酸片段，它不是与蛋白质编码序列连续合成的。5‘端保守序列的供体是一个小的非多聚腺苷转录本，剪接的Leader RNA(SL RNA)(1)。SL RNA的5‘端39个核苷酸片段在转录后被反式剪接到所有消息。原生动物寄生虫Herpetomonas samuelpesoai的SL RNA基因已被克隆和测序。根据其与布氏锥虫SL-39聚体特异的寡核苷酸探针在基因组Southern blotts中的杂交(数据未示出)，600bp的HindIII限制性内切酶片段被鉴定为SL RNA编码片段。DNA序列分析表明，该片段可编码98个核苷酸的转录本，该转录本具有其他锥虫SL RNAs的特征(1)，5‘端的39-NT序列与其他SL RNA互补，在反式剪接的39-聚体之后保守的GT残基，Sm蛋白结合位点(PUA[U]nGPu)和转录本3’端的10个T残基。605bp的片段还包含118bp的序列，该序列与锥虫5S rRNA序列同源，起始于SL RNA编码区(2)下游120bp。Southern杂交分析表明，这种交替排列成串联重复序列的SL和5S RNA基因的排列代表了这些基因在Samuelpesoai基因组中的唯一基因座(数据未显示)。在兰氏线虫(T.rangeli)(2)、间日圆线虫(T.vivax)(2)和一些线虫(3、4、5)中已报道了5S和SL RNA基因的遗传连锁。在远亲生物体中保持这种联系可能对这个组织具有重要的功能意义。
In Trypanosomatidae, the 5'-ends of mature messages contain a conserved nucleotide segment which is not contiguously synthesized with the protein coding sequences. The donor of the 5'-end conserved sequence is a small non-polyadenylated transcript, Spliced Leader RNA (SL RNA)(1). The 5'-end 39 nt segment of the SL RNA is trans-spliced to all messages post-transcriptionally. SL RNA gene for the protozoan parasite Herpetomonas samuelpessoai has been cloned and sequenced. The 600-bp HindIII restriction enzyme fragment was identified as the SL RNA coding segment based on its hybridization to T. brucei SL-39-mer-specific oligonucleotide probes in genomic Southern blots (data not shown). The DNA sequence analysis of this fragment shows that it can code for a 98 nt transcript which has the hallmarks of SL RNAs identified in other trypanosomatids (1); a 5'-end 39-nt sequence complementary to other SL RNAs, conserved GT residue following the trans-spliced 39-mer, an Sm protein binding site (PuA [U] nGPu) and a stretch of 10 T residues at the 3'-end of the transcript. The 605-bp fragment also contains a 118 bp sequence homologous to trypanosomatid 5S rRNA sequences starting 120 bp downstream of the SL RNA coding region (2). Southern blot analysis suggests that this arrangement of alternating SL and 5S RNAgenes organized into tandem repeats represents the only locus for these genes in H. samuelpessoai genome (data not shown). The genetic linkage of 5S and SL RNA genes has been reported in T. rangeli (2), T. vivax (2) and in some nematodes (3, 4, 5). The conservation of this linkage in distantly related organisms may suggest a functional significance to this organization.