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 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 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.

scholarly journals Multiple copies of a retroposon interrupt spliced leader RNA genes in the African trypanosome, Trypanosoma gambiense.

1987 ◽  
Vol 6 (12) ◽  
pp. 3819-3826 ◽  
Author(s):  
S. Aksoy ◽  
T. M. Lalor ◽  
J. Martin ◽  
L. H. Van der Ploeg ◽  
F. F. Richards
Keyword(s):  
African Trypanosome ◽  
Spliced Leader ◽  
Multiple Copies ◽  
Rna Genes ◽  
Trypanosoma Gambiense ◽  
Spliced Leader Rna

Diplonema spp. Possess Spliced Leader RNA Genes Similar to the Kinetoplastida

2001 ◽  
Vol 48 (3) ◽  
pp. 325-331 ◽  
Author(s):  
NANCY R. STURM ◽  
DMITRI A. MASLOV ◽  
EDMUNDO C. GRISARD ◽  
DAVID A. CAMPBELL
Keyword(s):  
Spliced Leader ◽  
Rna Genes ◽  
Spliced Leader Rna

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.

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