scholarly journals Reverse Transcription in the Saccharomyces cerevisiae Long-Terminal Repeat Retrotransposon Ty3

Viruses ◽  
2017 ◽  
Vol 9 (3) ◽  
pp. 44 ◽  
Author(s):  
Jason Rausch ◽  
Jennifer Miller ◽  
Stuart Le Grice
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Long Terminal Repeat ◽  
Reverse Transcription ◽  
Terminal Repeat ◽  
Long Terminal Repeat Retrotransposon

RNA Lariat Debranching Enzyme as a Retroviral and Long-Terminal-Repeat Retrotransposon Host Factor

2020 ◽  
Vol 7 (1) ◽  
pp. 189-202
Author(s):  
Thomas M. Menees
Keyword(s):  
Long Terminal Repeat ◽  
Viral Entry ◽  
Reverse Transcription ◽  
Immune Deficiency Syndrome ◽  
Terminal Repeat ◽  
Host Factors ◽  
Branch Points ◽  
Debranching Enzyme ◽  
Long Terminal Repeat Retrotransposon ◽  
Hiv 1

Host cell factors are integral to viral replication. Human immunodeficiency virus 1 (HIV-1), the retroviral agent of acquired immune deficiency syndrome, requires several host factors for reverse transcription of the viral genomic RNA (gRNA) into DNA shortly after viral entry. One of these host factors is the RNA lariat debranching enzyme (Dbr1), which cleaves the 2′–5′ bond of branched and lariat RNAs. A recent study has revealed that Dbr1 cleaves HIV-1 gRNA lariats that form early after viral entry. Without Dbr1 activity, HIV-1 reverse transcription stalls, consistent with blockage of viral reverse transcriptase at gRNA branch points. These findings echo an earlier study with the long-terminal-repeat retrotransposon of Saccharomyces cerevisiae, Ty1, which is a retrovirus model. Currently, branching and debranching of viral gRNA are not widely recognized as features of HIV-1 replication, and the role of a gRNA lariat is not known. Future studies will determine whether these gRNA dynamics represent fundamental features of retroviral biology and whether they occur for other positive-sense RNA viruses.

scholarly journals The Self Primer of the Long Terminal Repeat Retrotransposon Tf1 Is Not Removed during Reverse Transcription

2006 ◽  
Vol 80 (16) ◽  
pp. 8267-8270 ◽  
Author(s):  
Angela Atwood-Moore ◽  
Kenneth Yan ◽  
Robert L. Judson ◽  
Henry L. Levin
Keyword(s):  
Long Terminal Repeat ◽  
Schizosaccharomyces Pombe ◽  
Reverse Transcription ◽  
Dominant Species ◽  
Rnase H ◽  
The Self ◽  
Terminal Repeat ◽  
Minus Strand ◽  
Long Terminal Repeat Retrotransposon ◽  
Unique Mechanism

ABSTRACT The long terminal repeat retrotransposon Tf1 of Schizosaccharomyces pombe uses a unique mechanism of self priming to initiate reverse transcription. Instead of using a tRNA, Tf1 primes minus-strand synthesis with an 11-nucleotide RNA removed from the 5′ end of its own transcript. We tested whether the self primer of Tf1 was similar to tRNA primers in being removed from the cDNA by RNase H. Our analysis of Tf1 cDNA extracted from virus-like particles revealed the surprising observation that the dominant species of cDNA retained the self primer. This suggests that integration of the cDNA relies on mechanisms other than reverse transcription to remove the primer.

scholarly journals A novel discovery of a long terminal repeat retrotransposon-induced hybrid weakness in rice

2018 ◽  
Vol 70 (4) ◽  
pp. 1197-1207
Author(s):  
Sadia Nadir ◽  
Wei Li ◽  
Qian Zhu ◽  
Sehroon Khan ◽  
Xiao-Ling Zhang ◽  
...  
Keyword(s):  
Long Terminal Repeat ◽  
Terminal Repeat ◽  
Long Terminal Repeat Retrotransposon ◽  
Hybrid Weakness

scholarly journals The L1Tc C-Terminal Domain from Trypanosoma cruzi Non-Long Terminal Repeat Retrotransposon Codes for a Protein That Bears Two C2H2 Zinc Finger Motifs and Is Endowed with Nucleic Acid Chaperone Activity

2005 ◽  
Vol 25 (21) ◽  
pp. 9209-9220 ◽  
Author(s):  
Sara R. Heras ◽  
Manuel C. López ◽  
José Luis García-Pérez ◽  
Sandra L. Martin ◽  
M. Carmen Thomas
Keyword(s):  
Nucleic Acid ◽  
Trypanosoma Cruzi ◽  
Long Terminal Repeat ◽  
Zinc Finger ◽  
Chaperone Activity ◽  
Terminal Repeat ◽  
Duplex Dna ◽  
Long Terminal Repeat Retrotransposon ◽  
Nucleic Acid Chaperone ◽  
Zinc Finger Motifs

ABSTRACT L1Tc, a non-long terminal repeat retrotransposon from Trypanosoma cruzi, is a 4.9-kb actively transcribed element which contains a single open reading frame coding for the machinery necessary for its autonomous retrotransposition. In this paper, we analyze the protein encoded by the L1Tc 3′ region, termed C2-L1Tc, which contains two zinc finger motifs similar to those present in the TFIIIA transcription factor family. C2-L1Tc binds nucleic acids with different affinities, such that RNA > tRNA > single-stranded DNA > double-stranded DNA, without any evidence for sequence specificity. C2-L1Tc also exhibits nucleic acid chaperone activity on different DNA templates that may participate in the mechanism of retrotransposition of the element. C2-L1Tc promotes annealing of complementary oligonucleotides, prevents melting of perfect DNA duplexes, and facilitates the strand exchange between DNAs to form the most stable duplex DNA in competitive displacement assays. Mapping of regions of C2-L1Tc using specific peptides showed that nucleic acid chaperone activity required a short basic sequence accompanied by a zinc finger motif or by another basic region such as RRR. Thus, a short basic polypeptide containing the two C2H2 motifs promotes formation of the most stable duplex DNA at a concentration only three times higher than that required for C2-L1Tc.

scholarly journals Evidence for the Packaging of Multiple Copies of Tf1 mRNA into Particles and the trans Priming of Reverse Transcription

2000 ◽  
Vol 74 (15) ◽  
pp. 7164-7170 ◽  
Author(s):  
Amanda Leigh Haag ◽  
Jia-Hwei Lin ◽  
Henry L. Levin
Keyword(s):  
Long Terminal Repeat ◽  
Schizosaccharomyces Pombe ◽  
Reverse Transcription ◽  
Terminal Repeat ◽  
Ltr Retrotransposon ◽  
Viral Mrna ◽  
Virus Like Particles ◽  
Multiple Copies ◽  
Close Relatives

ABSTRACT Long terminal repeat (LTR)-containing retrotransposons and retroviruses are close relatives that possess similar mechanisms of reverse transcription. The particles of retroviruses package two copies of viral mRNA that both function as templates for the reverse transcription of the element. We studied the LTR-retrotransposon Tf1 ofSchizosaccharomyces pombe to test whether multiple copies of transposon mRNA participate in the production of cDNA. Using the unique self-priming property of Tf1, we obtained evidence that multiple copies of Tf1 mRNA were packaged into virus-like particles. By coexpressing two distinct versions of Tf1, we found that the bulk of reverse transcription that was initiated on one mRNA template was subsequently transferred to others. In addition, the first 11 nucleotides of one mRNA were able to prime, in trans, the reverse transcription of another mRNA.

scholarly journals A Nucleocapsid Functionality Contained within the Amino Terminus of the Ty1 Protease That Is Distinct and Separable from Proteolytic Activity

2002 ◽  
Vol 76 (1) ◽  
pp. 346-354 ◽  
Author(s):  
Joseph F. Lawler ◽  
Gennady V. Merkulov ◽  
Jef D. Boeke
Keyword(s):  
Life Cycle ◽  
Long Terminal Repeat ◽  
Proteolytic Activity ◽  
Reverse Transcription ◽  
Protein S ◽  
Terminal Repeat ◽  
Amino Terminus ◽  
Carboxy Terminus ◽  
Gag Protein ◽  
Virus Like Particles

ABSTRACT Ty1 is the most successful of the five endogenous yeast retrotransposons. The life cycle of Ty1 dictates that a number of nucleocapsid (NC)-facilitated events occur although the protein(s) responsible for these events has not been identified. The positioning of the NC peptide is conserved at the carboxy terminus of the Gag protein among most long terminal repeat (LTR)-containing retroelements. An analogous region of Ty1 that simultaneously encodes part of Gag, protease (PR), and the C-terminal p4 peptide was mutagenized. Some of these mutations result in smaller-than-normal virus-like particles (VLPs). The mutants were also found to impair an NC-like functionality contained within the amino terminus of the protease that is distinct and separable from its proteolytic activity. Remarkably, these mutants have distinct defects in reverse transcription.

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