TY - JOUR
T1 - Structural and functional analysis of the Entamoeba histolytica EhrabB gene promoter
AU - Romero-Díaz, Mónica
AU - Gómez, Consuelo
AU - López-Reyes, Israel
AU - Martínez, Máximo B.
AU - Orozco, Esther
AU - Rodríguez, Mario A.
PY - 2007/9/20
Y1 - 2007/9/20
N2 - Background: The Entamoeba histolytica EhrabB gene encodes for a Rab GTPase involved in phagocytosis. It is located at a virulence locus where the Ehcp112 gene is in the complementary strand at 332 bp of EhrabB start codon, suggesting a finely regulated transcription of both genes. However, the transcription regulation in this parasite is poorly understood. Results: To initiate the knowledge of EhrabB gene expression regulation, here we studied the structural characteristics of its gene promoter and its control transcription elements. In silico searches of the EhrabB 5′-flanking region revealed that it contains a motif similar to the upstream regulatory element 1 (URE1) of the E. histolytica hgl5 gene. It also has sequences with homology to C/EBP and GATA1 binding sites, and heat shock elements (HSE). Primer extension experiments revealed that EhrabB has at least four transcription initiation sites. The elements at the 5′-flanking region that drive EhrabB gene expression were detected and characterized using transitory transfected trophozoites with a plasmid carrying the CAT reporter gene. EhrabB transcription is negatively regulated by a sequence located between positions -491 to -428 with respect to the first transcription initiation site. We also showed that the URE1-like motif activates EhrabB transcription. In addition, heat shock activated the EhrabB promoter in episomal constructs and lead to an increase in de novo EhrabB transcription. Conclusion: The data suggest that EhrabB transcription is controlled negatively by an unidentified sequence, but it is activated by an URE1-like motif. Our analyses also revealed the presence of activator HSE that function under stress.
AB - Background: The Entamoeba histolytica EhrabB gene encodes for a Rab GTPase involved in phagocytosis. It is located at a virulence locus where the Ehcp112 gene is in the complementary strand at 332 bp of EhrabB start codon, suggesting a finely regulated transcription of both genes. However, the transcription regulation in this parasite is poorly understood. Results: To initiate the knowledge of EhrabB gene expression regulation, here we studied the structural characteristics of its gene promoter and its control transcription elements. In silico searches of the EhrabB 5′-flanking region revealed that it contains a motif similar to the upstream regulatory element 1 (URE1) of the E. histolytica hgl5 gene. It also has sequences with homology to C/EBP and GATA1 binding sites, and heat shock elements (HSE). Primer extension experiments revealed that EhrabB has at least four transcription initiation sites. The elements at the 5′-flanking region that drive EhrabB gene expression were detected and characterized using transitory transfected trophozoites with a plasmid carrying the CAT reporter gene. EhrabB transcription is negatively regulated by a sequence located between positions -491 to -428 with respect to the first transcription initiation site. We also showed that the URE1-like motif activates EhrabB transcription. In addition, heat shock activated the EhrabB promoter in episomal constructs and lead to an increase in de novo EhrabB transcription. Conclusion: The data suggest that EhrabB transcription is controlled negatively by an unidentified sequence, but it is activated by an URE1-like motif. Our analyses also revealed the presence of activator HSE that function under stress.
UR - http://www.scopus.com/inward/record.url?scp=35948933041&partnerID=8YFLogxK
U2 - 10.1186/1471-2199-8-82
DO - 10.1186/1471-2199-8-82
M3 - Artículo
C2 - 17883848
SN - 1471-2199
VL - 8
JO - BMC Molecular Biology
JF - BMC Molecular Biology
M1 - 82
ER -