Identification of putative regulatory motifs in the upstream regions of co-expressed functional groups of genes in Plasmodium falciparumReportar como inadecuado

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BMC Genomics

, 10:18

First Online: 13 January 2009Received: 13 June 2008Accepted: 13 January 2009


BackgroundRegulation of gene expression in Plasmodium falciparum Pf remains poorly understood. While over half the genes are estimated to be regulated at the transcriptional level, few regulatory motifs and transcription regulators have been found.

ResultsThe study seeks to identify putative regulatory motifs in the upstream regions of 13 functional groups of genes expressed in the intraerythrocytic developmental cycle of Pf. Three motif-discovery programs were used for the purpose, and motifs were searched for only on the gene coding strand. Four motifs – the -G-rich-, the -C-rich-, the -TGTG- and the -CACA- motifs – were identified, and zero to all four of these occur in the 13 sets of upstream regions. The -CACA motif- was absent in functional groups expressed during the ring to early trophozoite transition. For functional groups expressed in each transition, the motifs tended to be similar. Upstream motifs in some functional groups showed -positional conservation- by occurring at similar positions relative to the translational start site TLS; this increases their significance as regulatory motifs. In the ribonucleotide synthesis, mitochondrial, proteasome and organellar translation machinery genes, G-rich, C-rich, CACA and TGTG motifs, respectively, occur with striking positional conservation. In the organellar translation machinery group, G-rich motifs occur close to the TLS. The same motifs were sometimes identified for multiple functional groups; differences in location and abundance of the motifs appear to ensure different modes of action.

ConclusionThe identification of positionally conserved over-represented upstream motifs throws light on putative regulatory elements for transcription in Pf.

AbbreviationsTLStranslational start site

PfPlasmodium falciparum

TFtranscription factor

TFBMtranscription factor binding motif

IDCintraerythrocytic developmental cycle

TAPtranscription associated protein

TSStranscription start site


UTRuntranslated region

hspheat shock protein

MAPmaximum a priori log likelihood

ESTexpressed sequence tag.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2164-10-18 contains supplementary material, which is available to authorized users.

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Autor: Prathima Iengar - NV Joshi


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