Genomic organisation and transcription characterisation of the gene encoding Leishmania (Leishmania) amazonensis arginase and its protein structure prediction

Silva, Edson Roberto da; Castilho, Tiago Moreno; Pioker, Fabiana Curtopassi; Silva, Carlos H. Tomich de Paula; Flöeter-Winter, Lucile Maria

doi:10.1016/s0020-7519(02)00002-4

Cited by 61 publications

(59 citation statements)

References 49 publications

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“…Similar results were obtained when meta 1 expression was normalized to arginase expression (data not shown), which is another gene thought to be stably expressed across the different stages of differentiation (da Silva et al 2002), in agreement with the pattern obtained from normalization to gapdh.…”

supporting

confidence: 87%

Correlation of meta 1 expression with culture stage, cell morphology and infectivity in Leishmania (Leishmania) amazonensis promastigotes

Santos

Silva

Zampieri

et al. 2011

Mem. Inst. Oswaldo Cruz

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supporting

confidence: 87%

Correlation of meta 1 expression with culture stage, cell morphology and infectivity in Leishmania (Leishmania) amazonensis promastigotes

Santos

Silva

Zampieri

et al. 2011

Mem. Inst. Oswaldo Cruz

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“…Ornithine, the amino acid from which polyamines are generated, is produced from arginine in mammalian cells by two genetically and biochemically distinct arginase (ARG) enzymes. An ARG activity has also been detected in Leishmania (26), and an arginase gene sequence from Leishmania amazonensis has been reported, although neither the gene nor protein was functionally characterized (27). ARG has also been touted as a potential antileishmanial drug target, because n-hydroxyarginine, an inhibitor of ARG that is produced by macrophages as an intermediate during the formation of nitric oxide, can reduce polyamine levels in Leishmania amastigotes and lowers parasite loads (28).…”

mentioning

confidence: 99%

Arginase Plays a Pivotal Role in Polyamine Precursor Metabolism in Leishmania

Roberts

Tancer

Polinsky

et al. 2004

Journal of Biological Chemistry

159

193

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The polyamine pathway of protozoan parasites has been successfully targeted in anti-parasitic therapies and is significantly different from that of the mammalian host. To gain knowledge into the metabolic routes by which parasites synthesize polyamines and their precursors, the arginase gene was cloned from Leishmania mexicana, and ⌬arg null mutants were created by double targeted gene replacement and characterized. The ARG sequence exhibited significant homology to ARG proteins from other organisms and predicted a peroxisomal targeting signal (PTS-1) that steers proteins to the glycosome, an organelle unique to Leishmania and related parasites. ARG was subsequently demonstrated to be present in the glycosome, whereas the polyamine biosynthetic enzymes, in contrast, were shown to be cytosolic. The ⌬arg knockouts expressed no ARG activity, lacked an intracellular ornithine pool, and were auxotrophic for ornithine or polyamines. The ability of the ⌬arg null mutants to proliferate could be restored by pharmacological supplementation, either with low putrescine or high ornithine or spermidine concentrations, or by complementation with an arginase episome. Transfection of an arg construct lacking the PTS-1 directed the synthesis of an arg that mislocalized to the cytosol and notably also complemented the genetic lesion and restored polyamine prototrophy to the ⌬arg parasites. This molecular, biochemical, and genetic dissection of ARG function in L. mexicana promastigotes establishes: (i) that the enzyme is essential for parasite viability; (ii) that Leishmania, unlike mammalian cells, expresses only one ARG activity; (iii) that the sole vital function of ARG is to provide polyamine precursors for the parasite; and (iv) that ARG is present in the glycosome, but this subcellular milieu is not essential for its role in polyamine biosynthesis.

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“…3A). Nucleotide sequence analysis of the longest cDNA demonstrated that two consecutive AG dinucleotides (positions -272 and -270) can be used as acceptor sites, while sequencing of the short cDNA showed that another two acceptor sites (positions -137 and -129) can either be used (da Silva et al 2002). Thus the two far apart regions can be used as acceptor sites, each one displaying a local micro-heterogeneity.…”

mentioning

confidence: 99%

“…-The majority of SL trans-splicing events so far described in kinetoplastids pointed to a precise use of 3' acceptor sites. However, many trials have shown that more than one acceptor site within the same intergenic region can be used in the generation of mature mRNAS coding the same ORF but distinct 5' UTR extensions (Vassella et al 1994, Nepomuceno-Silva et al 2001, da Silva et al 2002, Manning-Cela et al 2002.…”

mentioning

confidence: 99%

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Pre-mRNA trans-splicing: from kinetoplastids to mammals, an easy language for life diversity

Mayer

Flöeter-Winter²

2005

Mem. Inst. Oswaldo Cruz

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Since the discovery that genes are split into intron and exons, the studies of the mechanisms involved in splicing pointed to presence of consensus signals in an attempt to generalize the process for all living cells. However, as discussed in the present review, splicing is a theme full of variations. The trans-splicing of pre-mRNAs, the joining of exons from distinct transcripts, is one of these variations with broad distribution in the phylogenetic tree. The biological meaning of this phenomenon is discussed encompassing reactions resembling a possible noise to mechanisms of gene expression regulation. All of them however, can contribute to the generation of life diversity.Key words: RNA processing -alternative trans-splicing -spliced leader RNA -trypanosomatids -nematodes -mammalian Most of the protein-coding eukaryotic genes display an interrupted structure alternating exons and introns. After transcription, introns must be removed from the primary transcript (pre-mRNA) to generate a translatable mature mRNA. It is interesting to note that the mature mRNA is constituted of 5' and 3' untranslatable regions (UTR) flanking the open reading frame (ORF) and that UTR are also exons. The precise excision of the introns and the joining of neighboring exons is a complex process generally named splicing, and when this processing occurs within a single pre-mRNA molecule it can also be called cis-splicing (Moore et al. 1993, Burge et al. 1999.Cis-splicing occurs in a two-step mechanism, each step consisting of a transesterification reaction (Moore et al. 1993) (Fig. 1A). The spliceosome, a ribonucleoprotein machinery composed of five small ribonucleoproteins (U1, U2, U4, U5, U6 snRNPs, named in relation to the kind of associated RNA molecule) and approximately 300 distinct proteins, is responsible for the splicing catalysis (Burge et al. 1999).Much effort was expended on the comprehension of the structure and dynamics of this complex machine during the splicing process, but the rules that discriminate introns and exons within the message are still poorly understood. Nevertheless, four conserved pre-mRNA sequence elements, which interact with the spliceosome, have been characterized as determinants in the splicing process (Moore et al. 1993, Burge et al. 1999 (Fig. 1C). In mammals, the 5' splice site consensus is AG/GURAGU (R for purine, /for splice site, bold for the dinucleotide 5' intron boundary) while the 3' splice site consensus is YAG/G (Y for pyrimidine, /for splice site, bold for the dinucleotides 3' intron boundary). There is also a conservation of nucleotide sequence around the branch point, CURAY (Y for pyrimidine, R for purine and A for branch Recently, other cis-regulatory elements were implicated in splice site recognition, e.g. the exonic splicing enhancers (ESEs) (Fig. 1C). ESEs are localized within exons and interact with a family of proteins rich in serine and arginine (SR proteins) that recruits the spliceosome to the proximal splice site .Although the presence of those consensuses was observed, it i...

show abstract

Genomic organisation and transcription characterisation of the gene encoding Leishmania (Leishmania) amazonensis arginase and its protein structure prediction

Cited by 61 publications

References 49 publications

Correlation of meta 1 expression with culture stage, cell morphology and infectivity in Leishmania (Leishmania) amazonensis promastigotes

Correlation of meta 1 expression with culture stage, cell morphology and infectivity in Leishmania (Leishmania) amazonensis promastigotes

Arginase Plays a Pivotal Role in Polyamine Precursor Metabolism in Leishmania

Pre-mRNA trans-splicing: from kinetoplastids to mammals, an easy language for life diversity

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