Dataset Information

Overview of the organization of protease genes in the genome of Leishmania spp.

ABSTRACT:

Background

The genus Leishmania includes protozoan parasites that are able to infect an array of phlebotomine and vertebrate species. Proteases are related to the capacity of these parasites to infect and survive in their hosts and are therefore classified as virulence factors.

Findings

By analyzing protease genes annotated in the genomes of four Leishmania spp [Leishmania (Leishmania) infantum, L. (L.) major, L. (L.) mexicana and L. (Viannia) braziliensis], these genes were found on every chromosome of these protozoa. Four protease classes were studied: metallo-, serine, cysteine and aspartic proteases. Metalloprotease genes predominate in the L. (V.) braziliensis genome, while in the other three species studied, cysteine protease genes prevail. Notably, cysteine and serine protease genes were found to be very abundant, as they were found on all chromosomes of the four studied species. In contrast, only three aspartic protease genes could be detected in these four species. Regarding gene conservation, a higher number of conserved alleles was observed for cysteine proteases (42 alleles), followed by metalloproteases (35 alleles) and serine proteases (15 alleles).

Conclusions

The present study highlights substantial differences in the organization of protease genes among L. (L.) infantum, L. (L.) major, L. (L.) mexicana and L. (V.) braziliensis. We observed significant distinctions in many protease features, such as occurrence, quantity and conservation. These data indicate a great diversity of protease genes among Leishmania species, an aspect that may be related to their adaptations to the peculiarities of each microenvironment they inhabit, such as the gut of phlebotomines and the immune cells of vertebrate hosts.

SUBMITTER: Silva-Almeida M

PROVIDER: S-EPMC4158035 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

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Publications

Overview of the organization of protease genes in the genome of Leishmania spp.

Silva-Almeida Mariana M Souza-Silva Franklin F Pereira Bernardo Acácio Santini BA Ribeiro-Guimarães Michelle Lopes ML Alves Carlos Roberto CR

Parasites & vectors 20140820

<h4>Background</h4>The genus Leishmania includes protozoan parasites that are able to infect an array of phlebotomine and vertebrate species. Proteases are related to the capacity of these parasites to infect and survive in their hosts and are therefore classified as virulence factors.<h4>Findings</h4>By analyzing protease genes annotated in the genomes of four Leishmania spp [Leishmania (Leishmania) infantum, L. (L.) major, L. (L.) mexicana and L. (Viannia) braziliensis], these genes were found ...[more]

PMID: 25142315

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Project description: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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Dataset Information

Overview of the organization of protease genes in the genome of Leishmania spp.

Background

Findings

Conclusions

Publications

Overview of the organization of protease genes in the genome of Leishmania spp.

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