NCBI updates.... G3N3.com: What's new for 'Trypanosomatids' in PubMed

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Sent on Saturday, 2009 Feb 28
Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

Items 1 -3 of 3

1: PLoS Pathog. 2009 Feb;5(2):e1000317. Epub 2009 Feb 27.

Differential Trypanosome Surface Coat Regulation by a CCCH Protein That Co-Associates with procyclin mRNA cis-Elements.

Walrad P, Paterou A, Acosta-Serrano A, Matthews KR.

Centre for Immunology, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom.

The genome of Trypanosoma brucei is unusual in being regulated almost entirely at the post-transcriptional level. In terms of regulation, the best-studied genes are procyclins, which encode a family of major surface GPI-anchored glycoproteins (EP1, EP2, EP3, GPEET) that show differential expression in the parasite's tsetse-fly vector. Although procyclin mRNA cis-regulatory sequences have provided the paradigm for post-transcriptional control in kinetoplastid parasites, trans-acting regulators of procyclin mRNAs are unidentified, despite intensive effort over 15 years. Here we identify the developmental regulator, TbZFP3, a CCCH-class predicted RNA binding protein, as an isoform-specific regulator of Procyclin surface coat expression in trypanosomes. We demonstrate (i) that endogenous TbZFP3 shows sequence-specific co-precipitation of EP1 and GPEET, but not EP2 and EP3, procyclin mRNA isoforms, (ii) that ectopic overexpression of TbZFP3 does not perturb the mRNA abundance of procyclin transcripts, but rather that (iii) their protein expression is regulated in an isoform-specific manner, as evidenced by mass spectrometric analysis of the Procyclin expression signature in the transgenic cell lines. The TbZFP3 mRNA-protein complex (TbZFP3mRNP) is identified as a trans-regulator of differential surface protein expression in trypanosomes. Moreover, its sequence-specific interactions with procyclin mRNAs are compatible with long-established predictions for Procyclin regulation. Combined with the known association of TbZFP3 with the translational apparatus, this study provides a long-sought missing link between surface protein cis-regulatory signals and the gene expression machinery in trypanosomes.

PMID: 19247446 [PubMed - in process]

Expression of procyclin mRNAs during cyclical transmission of Trypanosoma brucei. [PLoS Pathog. 2005]
Identification and stage-specific association with the translational apparatus of TbZFP3, a CCCH protein that promotes trypanosome life-cycle development. [J Biol Chem. 2006]
The surface coat of procyclic Trypanosoma brucei: programmed expression and proteolytic cleavage of procyclin in the tsetse fly. [Proc Natl Acad Sci U S A. 2001]
ReviewGenetic controls for the expression of surface antigens in African trypanosomes. [Annu Rev Microbiol. 1994]
ReviewTranscription of protein-coding genes in trypanosomes by RNA polymerase I. [Annu Rev Microbiol. 1997]

2: Rev Bras Parasitol Vet. 2008 Jul-Sep;17(3):123-127.

[Canine visceral leishmaniasis evaluation in Poxoréo, Mato Grosso State, Brazil.]

[Article in Portuguese]

Azevedo MA, Dias AK, Paula HB, Perri SH, Nunes CM.

Curso de Medicina Veterinária, Departamento de Apoio, Produção e Saúde Animal/UNESP, Rua Clóvis Pestana, 793, Jardim D. Amélia, Araçatuba, SP, 16050-680, Brasil. caris@fmva.unesp.br.

Dogs play an important role as reservoir in the domestic cycle of visceral leishmaniasis, a serious public health problem. An epidemiological survey in 1,112 dogs was conducted at the Municipality of Poxoréo State of Mato Grosso, Brazil, using indirect immunofluorescence antibody test where the prevalence was 7.8%. Significant association was found between prevalence of canine visceral leishmaniasis and age of the dogs. Clinical signs and presence of other animals in the backyard, like chicken being more likely associated with seropositivity. Gender, garbage collection in the residence and family financial income were not associated with visceral leishmaniasis prevalence. Analysis of the results suggests that dogs aging more than 7 years and presence of another animal species co-inhabiting with the dogs may be risk factors for canine visceral leishmaniasis.

PMID: 19245756 [PubMed - as supplied by publisher]