Evolution of Tubulin Gene Arrays in Trypanosomatid parasites: genomic restructuring in Leishmania

Jackson, Andrew P.; Vaughan, Sue; Gull, Keith

doi:10.1186/1471-2164-7-261

Cited by 21 publications

(19 citation statements)

References 65 publications

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“…These include well-characterized surface proteins (PSA2/GP46) (Devault and Banuls 2008), amastin ( Jackson 2010), GP63/leishmanolysin Halle et al 2009), structural proteins (alpha-and beta-tubulin) (Jackson et al 2006), 40S ribosomal protein (EF1A), and chaperones (HSP70 and HSP83). In L. major Friedlin, the tandem array containing the largest number of gene copies was a class I nuclease-like protein, with sequence similarity to externally orientated surface membrane enzymes with 39-nucleotidase activity (Yamage et al 2000).…”

Section: Gene Copy Number Variation In Leishmaniamentioning

confidence: 99%

Chromosome and gene copy number variation allow major structural change between species and strains of Leishmania

Rogers¹,

Hilley²,

Dickens³

et al. 2011

Genome Res.

413

526

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Leishmania parasites cause a spectrum of clinical pathology in humans ranging from disfiguring cutaneous lesions to fatal visceral leishmaniasis. We have generated a reference genome for Leishmania mexicana and refined the reference genomes for Leishmania major, Leishmania infantum, and Leishmania braziliensis. This has allowed the identification of a remarkably low number of genes or paralog groups (2, 14, 19, and 67, respectively) unique to one species. These were found to be conserved in additional isolates of the same species. We have predicted allelic variation and find that in these isolates, L. major and L. infantum have a surprisingly low number of predicted heterozygous SNPs compared with L. braziliensis and L. mexicana. We used short read coverage to infer ploidy and gene copy numbers, identifying large copy number variations between species, with 200 tandem gene arrays in L. major and 132 in L. mexicana. Chromosome copy number also varied significantly between species, with nine supernumerary chromosomes in L. infantum, four in L. mexicana, two in L. braziliensis, and one in L. major. A significant bias against gene arrays on supernumerary chromosomes was shown to exist, indicating that duplication events occur more frequently on disomic chromosomes. Taken together, our data demonstrate that there is little variation in unique gene content across Leishmania species, but large-scale genetic heterogeneity can result through gene amplification on disomic chromosomes and variation in chromosome number. Increased gene copy number due to chromosome amplification may contribute to alterations in gene expression in response to environmental conditions in the host, providing a genetic basis for disease tropism.

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Section: Gene Copy Number Variation In Leishmaniamentioning

confidence: 99%

Chromosome and gene copy number variation allow major structural change between species and strains of Leishmania

Rogers¹,

Hilley²,

Dickens³

et al. 2011

Genome Res.

413

526

View full text Add to dashboard Cite

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“…Investigation of MEPs is a very challenging task in modern proteome analysis due to their poor solubility but following the protocols of Molloy et al [7], and Pavkova et al [8] we have successfully solubilized the membrane proteins with almost negligible remnants. Using this approach membrane subproteomes of some protozoans such as Trypanosoma sp [18]. and Plasmodium sp [19].…”

Section: Figurementioning

confidence: 99%

Proteome mapping of overexpressed membrane‐enriched and cytosolic proteins in sodium antimony gluconate (SAG) resistant clinical isolate of Leishmania donovani

Kumar

Sisodia

Misra

et al. 2010

Brit J Clinical Pharma

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WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Over 60% of patients with visceral leishmaniasis (VL) in India and Sudan have become unresponsive to treatment with pentavalent antimonials, the first line of drugs for over 60 years. The drug resistance mechanism, studied so far in in vitro selected laboratory strains, has been attributed to various biochemical parameters. The resistance to Sb (V) in Leishmania field isolates is still unexplored. WHAT THIS STUDY ADDS In order to elucidate for the first time the mechanism of drug resistance in field isolates, this study was done in those clinically relevant field isolates which were either responsive or non responsive to SAG. A comparison of proteome profiles of membrane‐enriched as well as cytosolic protein fractions of these isolates has pinpointed the multiple overexpressed proteins in resistant isolates. This study has indicated their possible essential role in antimony resistance of the parasite and provides a vast field to be exploited to find much needed novel treatment strategies against VL. AIMS This study aimed to identify differentially overexpressed membrane‐enriched as well as cytosolic proteins in SAG sensitive and resistant clinical strains of L. donovani isolated from VL patients which are involved in the drug resistance mechanism. METHODS The proteins in the membrane‐enriched as well as cytosolic fractions of drug‐sensitive as well as drug‐resistant clinical isolates were separated using two‐dimensional gel electrophoresis and overexpressed identified protein spots of interest were excised and analysed using MALDI‐TOF/TOF. RESULTS Six out of 12 overexpressed proteins were identified in the membrane‐enriched fraction of the SAG resistant strain of L. donovani whereas 14 out of 18 spots were identified in the cytosolic fraction as compared with the SAG sensitive strain. The major proteins in the membrane‐enriched fraction were ABC transporter, HSP‐83, GPI protein transamidase, cysteine–leucine rich protein and 60S ribosomal protein L23a whereas in the cytosolic fraction proliferative cell nuclear antigen (PCNA), proteasome alpha 5 subunit, carboxypeptidase, HSP‐70, enolase, fructose‐1,6‐bisphosphate aldolase, tubulin‐beta chain have been identified. Most of these proteins have been reported as potential drug targets, except 60S ribosomal protein L23a and PCNA which have not been reported to date for their possible involvement in drug resistance against VL. CONCLUSION This study for the first time provided a cumulative proteomic analysis of proteins overexpressed in drug resistant clinical isolates of L. donovani indicating their possible role in antimony resistance of the parasite. Identified proteins provide a vast field to be exploited for novel treatment strategies against VL such as cloning and overexpression of these targets to produce recombinant therapeutic/prophylactic proteins.

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“…Classical studies demonstrated that the promastigote stage synthesizes more tubulin protein than the amastigote stage, and that this biosynthetic change of tubulin was found to correlate with the morphological change of microtubules in leishmanial flagella and cytoskeleton during promastigote-to-amastigote transformation [5]. Studies aimed to uncover the regulation responsible for the differential expression of tubulin genes were initiated shortly after [6], but this has resulted to be a difficult task due to the complex genome organization of tubulin genes [7], in particular, and to the non-conventional mechanisms of gene regulation operating in Leishmania [8]. …”

Section: Introductionmentioning

confidence: 99%

“…In various Leishmania species, the genomic organization of α- and β-tubulin genes has been analyzed, showing the existence of multiple copies, both arranged in tandem (forming separate clusters of α- and β-tubulin genes) and dispersed in the genome [7,9,10]. The availability of the genome sequences for several Leishmania species [11-13] has allowed resolving questions regarding the genome organization of complex gene families.…”

Section: Introductionmentioning

confidence: 99%

Alpha tubulin genes from Leishmania braziliensis:genomic organization, gene structure and insights on their expression

2013

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BackgroundAlpha tubulin is a fundamental component of the cytoskeleton which is responsible for cell shape and is involved in cell division, ciliary and flagellar motility and intracellular transport. Alpha tubulin gene expression varies according to the morphological changes suffered by Leishmania in its life cycle. However, the objective of studying the mechanisms responsible for the differential expression has resulted to be a difficult task due to the complex genome organization of tubulin genes and to the non-conventional mechanisms of gene regulation operating in Leishmania.ResultsWe started this work by analyzing the genomic organization of α-tubulin genes in the Leishmania braziliensis genome database. The genomic organization of L. braziliensis α-tubulin genes differs from that existing in the L. major and L. infantum genomes. Two loci containing α-tubulin genes were found in the chromosomes 13 and 29, even though the existence of sequence gaps does not allow knowing the exact number of genes at each locus. Southern blot assays showed that α-tubulin locus at chromosome 13 contains at least 8 gene copies, which are tandemly organized with a 2.08-kb repetition unit; the locus at chromosome 29 seems to contain a sole α-tubulin gene. In addition, it was found that L. braziliensis α-tubulin locus at chromosome 13 contains two types of α-tubulin genes differing in their 3′ UTR, each one presumably containing different regulatory motifs. It was also determined that the mRNA expression levels of these genes are controlled by post-transcriptional mechanisms tightly linked to the growth temperature. Moreover, the decrease in the α-tubulin mRNA abundance observed when promastigotes were cultured at 35°C was accompanied by parasite morphology alterations, similar to that occurring during the promastigote to amastigote differentiation.ConclusionsInformation found in the genome databases indicates that α-tubulin genes have been reorganized in a drastic manner along Leishmania speciation. In the L. braziliensis genome database, two loci containing α-tubulin sequences were found, but only the locus at chromosome 13 contains the prototypic α-tubulin genes, which are repeated in a head-to-tail manner. Also, we determined that the levels of α-tubulin mRNAs are down-regulated drastically in response to heat shock by a post-transcriptional mechanism which is dependent upon active protein synthesis.

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Evolution of Tubulin Gene Arrays in Trypanosomatid parasites: genomic restructuring in Leishmania

Cited by 21 publications

References 65 publications

Chromosome and gene copy number variation allow major structural change between species and strains of Leishmania

Chromosome and gene copy number variation allow major structural change between species and strains of Leishmania

Proteome mapping of overexpressed membrane‐enriched and cytosolic proteins in sodium antimony gluconate (SAG) resistant clinical isolate of Leishmania donovani

Alpha tubulin genes from Leishmania braziliensis:genomic organization, gene structure and insights on their expression

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