A type II ribonuclease H from Leishmania mitochondria: An enzyme essential for the growth of the parasite

Misra, Smita; Bennett, Jabbar; Friew, Yeshitila N; Abdulghani, Junaid; Irvin-Wilson, Charletha V.; Tripathi, Manish Kumar; Williams, Scott A.; Chaudhuri, Minu; Chaudhuri, Gautam

doi:10.1016/j.molbiopara.2005.05.009

Cited by 11 publications

(11 citation statements)

References 32 publications

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“…a ) Spots match ID number obtained from ImageMaster Platinum;b ) Name of the identified protein;c ) Uniprot identification code;d ) Experimentally predicted and expected isoelectric point ( pI );e ) Experimentally predicted and expected molecular weight ( Mr , in kDa);f ) Number of identified peptides by MS;g ) Percentage of the protein sequence covered by identified peptides;h ) Normalized data from R0 represented by mean values of each condition divided by R30 value;i ) Fold represents the maximum spot intensity mean value of the conditions divided by the smallest value;j ) One-way ANOVA ( P <0.01) obtained from spot analysis;k ) Biological functions according to NCBI, UniProt, and Gene Ontology databases;l ) Biological activity and/or immunological application described in other studies: [22] Tull et al, 2010; [23] Oliveira et al, 2006; [24] Daifalla et al, 2011; [25] Iyer et al, 2008; [26] Hunger-Glaser et al, 1999; [27] Werbovetz et al, 1999; [28] Feng et al, 2011; [29] Niemirowicz et al, 2007; [30] Hunger-Glaser et al, 1997; [31] Alcolea et al, 2009; [32] Bhaskar et al, 2012; [33] Khanra et al, 2012; [34] Berberich et al, 2003; [35] Moore et al, 1996; [36] Swenerton et al, 2011; [37] Hummadi et al, 2006; [38] Martins et al, 2006; [39] Burns et al, 1993; [40] Kushawaha et al, 2011; [41] Misra et al, 2005; [42] Bringaud et al, 1995; [43] Eggleson et al, 1999; [44] Mureev et al, 2007; [45] Steiner et al, 2007; [46] Martínez-Rodríguez et al, 2012; [47] Drummelsmith et al, 2004; [48] Achour et al, 2002; [49] Buda et al, 2013; [50] Alcolea et al, 2011; [51] Martín et al, 2009; [52] Silva et al, 2012. The proteins were identified through the data included in ...…”

Section: Resultsmentioning

confidence: 99%

Identification of Differentially Expressed Proteins from Leishmania amazonensis Associated with the Loss of Virulence of the Parasites

et al. 2014

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BackgroundThe present study analyzed whether or not the in vitro cultivation for long periods of time of pre-isolated Leishmania amazonensis from lesions of chronically infected BALB/c mice was able to interfere in the parasites' infectivity using in vivo and in vitro experiments. In addition, the proteins that presented a significant decrease or increase in their protein expression content were identified applying a proteomic approach.Methodology/Principal FindingsParasites were cultured in vitro for 150 days. Aliquots were collected on the day 0 of culture (R0), as well as after ten (R10; 50 days of culture), twenty (R20; 100 days of culture), and thirty (R30; 150 days of culture) passages, and were used to analyze the parasites' in vitro and in vivo infectivity, as well as to perform the proteomic approach. Approximately 837, 967, 935, and 872 spots were found in 2-DE gels prepared from R0, R10, R20, and R30 samples, respectively. A total of 37 spots presented a significant decrease in their intensity of expression, whereas a significant increase in protein content during cultivation could be observed for 19 proteins (both cases >2.0 folds). Some of these identified proteins can be described, such as diagnosis and/or vaccine candidates, while others are involved in the infectivity of Leishmania. It is interesting to note that six proteins, considered hypothetical in Leishmania, showed a significant decrease in their expression and were also identified.Conclusions/SignificanceThe present study contributes to the understanding that the cultivation of parasites over long periods of time may well be related to the possible loss of infectivity of L. amazonensis. The identified proteins that presented a significant decrease in their expression during cultivation, including the hypothetical, may also be related to this loss of parasites' infectivity, and applied in future studies, including vaccine candidates and/or immunotherapeutic targets against leishmaniasis.

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Section: Resultsmentioning

confidence: 99%

Identification of Differentially Expressed Proteins from Leishmania amazonensis Associated with the Loss of Virulence of the Parasites

et al. 2014

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“…The main function of RNase H is to remove RNA primers from Okazaki fragments, process R loops to modulate replication initiation and restore DNA topology (Broccoli et al, 2004;Kogoma & Foster 1998;Arudchandran et al, 2000). Recently, a mitochondrial RNase H from the parasitic protozoon Leishmania was analysed, which is essential for the parasite's survival (Misra et al, 2005). This may give a clue to the biological status of the Cpn-RNase Hs, which may play an important role on the DNA replication/ translation processes of Chlamydophila and may be vital for this organism.…”

Section: Discussionmentioning

confidence: 99%

Biochemical characterization and functional complementation of ribonuclease HII and ribonuclease HIII from Chlamydophila pneumoniae AR39

et al. 2007

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Chlamydophila pneumoniae AR39 contains two different ORFs (CP0654 and CP0782) encoding ribonuclease H (RNase H) homologues, Cpn-RNase HII and Cpn-RNase HIII. Sequence alignments show that the two homologues both contain the conserved motifs of type 2 RNase H, and Cpn-RNase HII has the conserved active-site motif (DEDD) of RNase HII. Cpn-RNase HIII also contains a unique active-site motif (DEDE), common to other RNase HIIIs. Complementation assays indicated that Cpn-RNase HII can complement both Escherichia coli RNase HII and RNase HI, but Cpn-RNase HIII can only complement the latter. In vitro enzyme activity experiments showed that neither Cpn-RNase HII nor Cpn-RNase HIII is thermostable and their optimum pH values were 9.0 and 10.0, respectively. Cpn-RNase HII cleaves a 12 bp RNA-DNA substrate at multiple sites, but Cpn-RNase HIII at only one site. When a 35 bp DNA-RNA-DNA/DNA chimeric substrate was used, cleavage was only observed with Cpn-RNase HII. These results indicate that the RNase H combination of C. pneumoniae AR39 is not simple substitution of E. coli RNase H, perhaps representing a more primordial type. This is believed to be the first in vivo functional study of Chlamydophila RNase Hs and the results should cntribute to the analysis of RNase Hs of other parasite species.

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“…In addition, three candidates for the T. brucei RNase H2 complex were revealed: Tb427.10.5070 was predicted to encode a protein highly similar to eukaryotic catalytic RNase H2A subunits, and Tb427.01.4220 and Tb427.01.4730 encode likely orthologues of RH2B and RH2C, respectively (Table S1, Fig.S1A). Surprisingly, synteny between these orthologues and three previously described RNase H2-like genes in Leishmania major [56] is not simple to discern. For instance, the putative T. brucei RNase H2A (TbRH2A) encoded by Tb427.10.5070 by shows greatest homology to, and is syntenic with, LmjF.36.0640, which has previously been named RNase HIIB [56](Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Surprisingly, synteny between these orthologues and three previously described RNase H2-like genes in Leishmania major [56] is not simple to discern. For instance, the putative T. brucei RNase H2A (TbRH2A) encoded by Tb427.10.5070 by shows greatest homology to, and is syntenic with, LmjF.36.0640, which has previously been named RNase HIIB [56](Fig. S1B).…”

Section: Resultsmentioning

confidence: 99%

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Trypanosoma bruceiribonuclease H2A is an essential enzyme that resolves R-loops associated with transcription initiation and antigenic variation

Briggs

Crouch

Lemgruber

et al. 2019

Preprint

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In every cell ribonucleotides represent a threat to the stability and transmission of the DNA genome. Two types of Ribonuclease H (RNase H) tackle such ribonucleotides, either by excision when they form part of the DNA strand, or by hydrolysing RNA when it base-pairs with DNA, in structures termed R-loops. Loss of either RNase H is lethal in mammals, whereas yeast can prosper in the absence of both enzymes. Removal of RNase H1 is tolerated by the parasite Trypanosoma brucei but no work has examined the function of RNase H2. Here we show that loss of the catalytic subunit of T. brucei RNase H2 (TbRH2A) leads to growth and cell cycle arrest that is concomitant with accumulation of nuclear damage at sites of RNA polymerase (Pol) II transcription initiation, revealing a novel and critical role for RNase H2. In addition, differential gene expression of both RNA Pol I and II transcribed genes occurs after TbRH2A loss, including patterns that may relate to cytosolic DNA accumulation in humans with autoimmune disease. Finally, we show that TbRH2A loss causes R-loop and DNA damage accumulation in telomeric RNA Pol I transcription sites, leading to altered variant surface glycoprotein expression. Thus, we demonstrate a separation of function between the two nuclear T. brucei RNase H enzymes during RNA Pol II transcription, but overlap in function during RNA Pol I-mediated gene expression during host immune evasion.

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A type II ribonuclease H from Leishmania mitochondria: An enzyme essential for the growth of the parasite

Abstract: Replication of kDNA in the mitochondrion of the kinetoplastid protozoan is an essential process.

Cited by 11 publications

References 32 publications

Identification of Differentially Expressed Proteins from Leishmania amazonensis Associated with the Loss of Virulence of the Parasites

Identification of Differentially Expressed Proteins from Leishmania amazonensis Associated with the Loss of Virulence of the Parasites

Biochemical characterization and functional complementation of ribonuclease HII and ribonuclease HIII from Chlamydophila pneumoniae AR39

Trypanosoma bruceiribonuclease H2A is an essential enzyme that resolves R-loops associated with transcription initiation and antigenic variation

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