trans-spliceosomal U6 RNAs of Crithidia fasciculata and Leptomonas seymouri: deviation from the conserved ACAGAG sequence and potential base pairing with spliced leader RNA

1994 ◽  
Vol 14 (7) ◽  
pp. 4565-4570
Author(s):  
G L Xu ◽  
B Wieland ◽  
A Bindereif
Keyword(s):  
Splice Site ◽  
Base Change ◽  
Trna Genes ◽  
Rna Sequences ◽  
Compensatory Base Change ◽  
Crithidia Fasciculata ◽  
Spliced Leader ◽  
Rna Genes ◽  
Spliced Leader Rna ◽  
U6 Rna

U6 RNA genes from the trypanosomatids Crithidia fasciculata and Leptomonas seymouri have been isolated and sequenced. As in Trypanosoma brucei, the U6 RNA genes in both C. fasciculata and L. seymouri are arranged in close linkage with upstream tRNA genes. The U6 RNA sequences from C. fasciculata and L. seymouri deviate in five and three positions, respectively, from the published T. brucei sequence. Interestingly, both C. fasciculata U6 RNA genes carry a C-->T change at the second position of the ACAGAG hexanucleotide sequence, which is important for splicing function and has been considered phylogenetically invariable. A compensatory base change of the C. fasciculata spliced leader RNA at the highly conserved 5' splice site position +5, G-->A, suggests that an interaction between the 5' splice site region and U6 RNA recently proposed for the yeast cis-splicing system may also occur in trans splicing.

scholarly journals trans-spliceosomal U6 RNAs of Crithidia fasciculata and Leptomonas seymouri: deviation from the conserved ACAGAG sequence and potential base pairing with spliced leader RNA.

1994 ◽  
Vol 14 (7) ◽  
pp. 4565-4570 ◽  
Author(s):  
G L Xu ◽  
B Wieland ◽  
A Bindereif
Keyword(s):  
Splice Site ◽  
Base Change ◽  
Trna Genes ◽  
Rna Sequences ◽  
Compensatory Base Change ◽  
Crithidia Fasciculata ◽  
Spliced Leader ◽  
Rna Genes ◽  
Spliced Leader Rna ◽  
U6 Rna

U6 RNA genes from the trypanosomatids Crithidia fasciculata and Leptomonas seymouri have been isolated and sequenced. As in Trypanosoma brucei, the U6 RNA genes in both C. fasciculata and L. seymouri are arranged in close linkage with upstream tRNA genes. The U6 RNA sequences from C. fasciculata and L. seymouri deviate in five and three positions, respectively, from the published T. brucei sequence. Interestingly, both C. fasciculata U6 RNA genes carry a C-->T change at the second position of the ACAGAG hexanucleotide sequence, which is important for splicing function and has been considered phylogenetically invariable. A compensatory base change of the C. fasciculata spliced leader RNA at the highly conserved 5' splice site position +5, G-->A, suggests that an interaction between the 5' splice site region and U6 RNA recently proposed for the yeast cis-splicing system may also occur in trans splicing.

Phylogenic analysis of Chinese Leishmania isolates based on small subunit ribosomal RNA (SSU rRNA) and 7 spliced leader RNA (7SL RNA)

2012 ◽  
Vol 57 (2) ◽  
Author(s):  
Wang Guan ◽  
De-Ping Cao ◽  
Ke sun ◽  
Jia-nan Xu ◽  
Jun-rong Zhang ◽  
...  
Keyword(s):  
Bayesian Analysis ◽  
Ribosomal Rna ◽  
Small Subunit ◽  
Ssu Rrna ◽  
Gene Sequences ◽  
Rna Sequences ◽  
Spliced Leader ◽  
Small Subunit Ribosomal Rna ◽  
7Sl Rna ◽  
Spliced Leader Rna

AbstractThe leishmaniases are zoonotic diseases caused by protozoan parasites of the genus Leishmania. Leishmaniases are still endemic in China, especially in the west and northwest froniter regions. To revalue the preliminary phylogenetic results of Chinese Leishmania isolates, we amplified partial fragment of small subunit ribosomal RNA (SSU rRNA) and 7 spliced leader RNA (7SL RNA), then tested the phylogenetic relationships among Chinese Leishmania isolates and their relatives by analyzing SSU rRNA gene sequences and 7SL RNA gene sequences. 19 SSU RNA sequences and 9 7SL RNA sequences were obtained in our study, then analyzed with 42 SSU RNA sequences and 32 7SL RNA sequences retrieved from Genbank, respectively. In the Bayesian analysis of the SSU RNA gene, the isolate MHOM/CN/93/GS7 and the isolate IPHL/CN/77/XJ771 are members of Leishmania donovani complex, while the isolate MHOM/CN/84/JS1 clustered with Leishmania tropica. The other 11 Chinese Leishmania isolates (MHOM/CN/90/WC, MCAN/CN/90/SC11, MHOM/CN/80/XJ801, MHOM/CN/85/GS4, MHOM/CN/84/SD1, MCAN/CN/86/SC7, MHOM/CN/54/#3, MHOM/CN/83/GS2, MHOM/CN/90/SC10H2, MHOM/CN/89/GS6 and MHOM/CN/ 89/GS5) form an unclassified group, defined as Leishmania sp., and the most relative species to this group is L. tarentolae. In the Bayesian analysis of the 7SL RNA gene, 9 Chinese Leishmania isolates also formed an unclassified group with L. tarentolae, including canine isolate 10, MHOM/CN/85/GS4, MHOM/CN/84/SD1, MCAN/CN/86/SC7, MHOM/CN/54/#3, MHOM/ CN/83/GS2, MHOM/CN/90/SC10H2, MHOM/CN/89/GS6 and MHOM/CN/89/GS5. We concluded that: (1) Chinese Leishmania isolates are non-monophyly group; (2) an unclassified group may exist in China, and the most relative species to this group is L. tarentolae; (3) MHOM/CN/84/JS1, which was previously assigned as L. donovani, was most genetically related to L. tropica strain MHOM/SU/74/K27.

scholarly journals Dinoflagellate Spliced Leader RNA Genes Display a Variety of Sequences and Genomic Arrangements

2009 ◽  
Vol 26 (8) ◽  
pp. 1757-1771 ◽  
Author(s):  
H. Zhang ◽  
D. A. Campbell ◽  
N. R. Sturm ◽  
S. Lin
Keyword(s):  
Spliced Leader ◽  
Rna Genes ◽  
Spliced Leader Rna

A new member of a family of site-specific retrotransposons is present in the spliced leader RNA genes of Trypanosoma cruzi

1991 ◽  
Vol 11 (12) ◽  
pp. 6139-6148
Author(s):  
M S Villanueva ◽  
S P Williams ◽  
C B Beard ◽  
F F Richards ◽  
S Aksoy
Keyword(s):  
Amino Acid ◽  
Trypanosoma Cruzi ◽  
Open Reading Frames ◽  
Amino Acid Homology ◽  
Site Specific ◽  
Reading Frame ◽  
Spliced Leader ◽  
Copy Numbers ◽  
Rna Genes ◽  
Spliced Leader Rna

A new member of a family of site-specific retrotransposons is described in the New World trypanosome Trypanosoma cruzi. This element, CZAR (cruzi-associated retrotransposon), resembles two previously described retrotransposons found in the African trypanosome T. brucei gambiense and the mosquito trypanosomatid Crithidia fasciculata in specifically inserting between nucleotides 11 and 12 of the highly conserved 39-mer of the spliced leader RNA (SL-RNA) gene. CZAR is similar in overall organization to the other two SL-RNA-associated elements. It possesses two potential long open reading frames which resemble the gag and pol genes of retroviruses. In the pol open reading frame, all three elements contain similarly arranged endonuclease domains and share extensive amino acid homology in the reverse transcriptase region. All are associated with the SL-RNA gene locus and are present in low copy numbers. They do not appear to have 5' truncated versions. All three retrotransposons are otherwise quite distinct from one another, with no significant overall amino acid homology. The presence of such retroelements inserted into the identical site within SL-RNA gene sequences in at least three evolutionarily distant trypanosomatid species argues for a functional role. Because these elements appear to have a precise target site requirement for integration, we refer to them as SL siteposons.

scholarly journals A new member of a family of site-specific retrotransposons is present in the spliced leader RNA genes of Trypanosoma cruzi.

1991 ◽  
Vol 11 (12) ◽  
pp. 6139-6148 ◽  
Author(s):  
M S Villanueva ◽  
S P Williams ◽  
C B Beard ◽  
F F Richards ◽  
S Aksoy
Keyword(s):  
Amino Acid ◽  
Trypanosoma Cruzi ◽  
Open Reading Frames ◽  
Amino Acid Homology ◽  
Site Specific ◽  
Reading Frame ◽  
Spliced Leader ◽  
Copy Numbers ◽  
Rna Genes ◽  
Spliced Leader Rna

A new member of a family of site-specific retrotransposons is described in the New World trypanosome Trypanosoma cruzi. This element, CZAR (cruzi-associated retrotransposon), resembles two previously described retrotransposons found in the African trypanosome T. brucei gambiense and the mosquito trypanosomatid Crithidia fasciculata in specifically inserting between nucleotides 11 and 12 of the highly conserved 39-mer of the spliced leader RNA (SL-RNA) gene. CZAR is similar in overall organization to the other two SL-RNA-associated elements. It possesses two potential long open reading frames which resemble the gag and pol genes of retroviruses. In the pol open reading frame, all three elements contain similarly arranged endonuclease domains and share extensive amino acid homology in the reverse transcriptase region. All are associated with the SL-RNA gene locus and are present in low copy numbers. They do not appear to have 5' truncated versions. All three retrotransposons are otherwise quite distinct from one another, with no significant overall amino acid homology. The presence of such retroelements inserted into the identical site within SL-RNA gene sequences in at least three evolutionarily distant trypanosomatid species argues for a functional role. Because these elements appear to have a precise target site requirement for integration, we refer to them as SL siteposons.

The evolution of spliced leader trans-splicing in nematodes

2010 ◽  
Vol 38 (4) ◽  
pp. 1125-1130 ◽  
Author(s):  
Jonathan Pettitt ◽  
Neale Harrison ◽  
Ian Stansfield ◽  
Bernadette Connolly ◽  
Berndt Müller
Keyword(s):  
Caenorhabditis Elegans ◽  
Common Ancestor ◽  
Model Organism ◽  
Spliced Leader ◽  
Trans Splicing ◽  
Rna Genes ◽  
Spliced Leader Rna

Spliced leader trans-splicing occurs in many primitive eukaryotes including nematodes. Most of our knowledge of trans-splicing in nematodes stems from the model organism Caenorhabditis elegans and relatives, and from work with Ascaris. Our investigation of spliced leader trans-splicing in distantly related Dorylaimia nematodes indicates that spliced-leader trans-splicing arose before the nematode phylum and suggests that the spliced leader RNA gene complements in extant nematodes have evolved from a common ancestor with a diverse set of spliced leader RNA genes.

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