Encystation-specific regulation of the cyst wall protein 2 gene in Giardia lamblia by multiple cis-acting elements

Davis-Hayman, Sara R.; Hayman, J. Russell; Nash, Theodore E.

doi:10.1016/s0020-7519(03)00177-2

Cited by 40 publications

(45 citation statements)

References 17 publications

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“…They are essential for promoter activity and play a predominant role in determining the positions of the transcription start sites (17)(18)(19). Specific regulatory regions have been identified in the encystationinduced cwp2 promoter, including a positive cis-acting element (Ϫ23 to Ϫ10 relative to the translation start site) required for encystation-specific promoter activity and a negative cis-acting element (Ϫ64 to Ϫ23 region) required for promoter activity in vegetative cells (21). The latter region also contains a region (Ϫ61 to Ϫ52) that controls sterol-mediated decrease in the cwp2 transcription (22).…”

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A Novel WRKY-like Protein Involved in Transcriptional Activation of Cyst Wall Protein Genes in Giardia lamblia

Pan

Cho

Kao

et al. 2009

Journal of Biological Chemistry

101

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Synthesis of a protective cyst wall is required for survival outside of the host and for infection of Giardia lamblia. Little is known of gene regulation of the cyst wall proteins (CWPs) during differentiation into dormant cysts. WRKY homologues constitute a large family of DNA-binding proteins in plants that are involved in several key cellular functions, including disease resistance, stress response, dormancy, and development. A putative wrky gene has been identified in the G. lamblia genome. We found that wrky expression levels increased significantly during encystation. The epitope-tagged WRKY was translocated into the nuclei during encystation. Recombinant WRKY specifically bound to its own promoter and the encystation-induced cwp1 and cwp2 promoters. WRKY contains several key residues for DNA binding, and mutation analysis revealed that its binding sequences are similar to those of the known plant WRKY proteins and that two of them are positive cis-acting elements of the wrky and cwp2 promoters. Overexpression of WRKY increased the cwp1-2 and myb2 mRNA levels, and these gene promoters were bound by WRKY in vivo. Interestingly, the wrky and cwp1-2 genes were up-regulated by ERK1 (extracellular signal-related kinase 1) overexpression, suggesting that WRKY may be a downstream component of the ERK1 pathway. In addition, a WRKY mutant that cannot enter nuclei and an ERK1 mutant lacking the predicted kinase domain showed decreased cwp1-2 gene expression. Our results suggest that the WRKY family has been conserved during evolution and that WRKY is an important transactivator of the cwp1-2 genes during G. lamblia differentiation into dormant cysts.

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confidence: 99%

A Novel WRKY-like Protein Involved in Transcriptional Activation of Cyst Wall Protein Genes in Giardia lamblia

Pan

Cho

Kao

et al. 2009

Journal of Biological Chemistry

101

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“…Therefore, the binding of some encystationspecific transcription factors to proximal upstream regions might be important for the selection of the upstream transcription start sites. Interestingly, in the cwp2 promoter, an encystation-specific regulatory element (Ϫ23 to Ϫ10 region) is just next to the gARID1 binding sequences/Inr (Ϫ8 to Ϫ1 region) (20), making it more likely that there is an interaction between regulatory and general transcription factors. It should be noted that, during both vegetative growth and encystation, the levels of both transcripts resulting from upstream or downstream transcription start sites decreased significantly when the gARID1 binding sequences/Inr were mutated, suggesting that the gARID1 binding sequences/Inr could be important for basal promoter activity.…”

Section: Discussionmentioning

confidence: 99%

“…It should be noted that, during both vegetative growth and encystation, the levels of both transcripts resulting from upstream or downstream transcription start sites decreased significantly when the gARID1 binding sequences/Inr were mutated, suggesting that the gARID1 binding sequences/Inr could be important for basal promoter activity. Deletion and mutation analysis of the ran, ␣2-tubulin, and cwp2 promoters has provided evidence for involvement of AT-rich Inr elements in basal promoter activity (15,16,20). In addition, there may be a synergistic effect between the upstream or downstream transcription start sites.…”

Section: Discussionmentioning

confidence: 99%

“…AT-rich sequences have been found spanning the transcription start sites of many genes, indicating that they are functionally similar to the initiator (Inr) 2 element in higher eukaryotes (8,9,11,(15)(16)(17)19). These sequences are essential for promoter activity and play a key role in determining the transcription start sites (16,17,20). Specific regulatory regions have been identified in the encystation-induced cwp2 promoter, including a positive cis-acting element (Ϫ23 to Ϫ10 relative to the translation start site) required for encystation-specific promoter activity and a negative cis-acting element (Ϫ64 to Ϫ23 region) required for promoter activity in vegetative cells (20).…”

mentioning

confidence: 99%

“…These sequences are essential for promoter activity and play a key role in determining the transcription start sites (16,17,20). Specific regulatory regions have been identified in the encystation-induced cwp2 promoter, including a positive cis-acting element (Ϫ23 to Ϫ10 relative to the translation start site) required for encystation-specific promoter activity and a negative cis-acting element (Ϫ64 to Ϫ23 region) required for promoter activity in vegetative cells (20). The latter region also contains a region (Ϫ61 to Ϫ52) that controls sterolmediated decrease in the cwp2 transcription (21).…”

mentioning

confidence: 99%

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A Novel ARID/Bright-like Protein Involved in Transcriptional Activation of Cyst Wall Protein 1 Gene in Giardia lamblia

Wang

Sun

2007

Journal of Biological Chemistry

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The capability of protozoan parasite Giardia lamblia to encyst is critical for survival outside the host and its transmission. AT-rich interaction domain (ARID) or Bright homologs constitute a large family of transcription factors in higher eukaryotes that regulate cell proliferation, development, and differentiation. We asked whether Giardia has ARID-like genes and whether they influence gene expression during Giardia encystation. Blast searches of the Giardia genome data base identified two genes with putative ARID/Bright domains (gARID1 and 2). Epitope-tagged gARID1 was found to localize to nuclei. Recombinant gARID1 specifically bound to the encystation-induced cyst wall protein (cwp) gene promoters. Mutation analysis revealed that AT-rich initiators were required for binding of gARID1 to the cwp promoters. gARID1 contains several key residues for DNA binding, and its binding sequences are similar to those of the known ARID family proteins. The gARID1 binding sequences were positive cis-acting elements of the cwp1 promoter during both vegetative growth and encystation. We also found that gARID1 transactivated the cwp1 promoter through its binding sequences in vivo. Our results suggest that the ARID family has been conserved during evolution and that gARID1 is an important transactivator in regulation of the Giardia cwp1 gene, which is key to Giardia differentiation into cysts.Giardia lamblia is an important human intestinal parasite that causes outbreaks of waterborne diarrheal disease (1, 2). It has two life cycle stages that are well adapted to survival in different inhospitable environments (3-6). The motile flagellated trophozoites attach to and colonize the human small intestine to cause the symptoms of giardiasis. The dormant infective cysts, which are protectively walled and resistant to external hostile conditions, are responsible for transmission of giardiasis.The ability of trophozoites to encyst in the intestine is key to Giardia pathophysiology. However, little is known of the regulation of encystation. Synthesis and secretion of specific proteins and polysaccharide required for the formation of a protective cyst wall is a major process of encystation (3, 5-7). Expression of genes encodes three cyst wall structural proteins (Cwp1, Cwp2, Cwp3) (8 -10), and glucosamine-6-phosphate isomerase-B, the first enzyme in the cyst wall polysaccharide biosynthetic pathway (11, 12), increases with similar kinetics during encystation (6, 9, 11, 12), suggesting the importance of regulation at the transcriptional level.G. lamblia is of significant evolutionary interest because it has been proposed as one of the most early diverging eukaryotes (13,14). The giardial transcription mechanism may be unusual because relatively short 5Ј-flanking regions (Ͻ65 bp) are sufficient for the expression of many constitutive and encystationinduced giardial genes (11,(15)(16)(17). No classical TATA or CCAAT boxes or other cis-acting elements have been found in the promoters of many giardial protein-coding genes (16, 18). AT-rich...

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Giardia

2011

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This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifi cally those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks.Product Liability: The publisher can give no guarantee for all the information contained in this book. This does also refer to information about drug dosage and application thereof. In every individual case the respective user must check its accuracy by consulting other pharmaceutical literature.The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

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Encystation-specific regulation of the cyst wall protein 2 gene in Giardia lamblia by multiple cis-acting elements

Cited by 40 publications

References 17 publications

A Novel WRKY-like Protein Involved in Transcriptional Activation of Cyst Wall Protein Genes in Giardia lamblia

A Novel WRKY-like Protein Involved in Transcriptional Activation of Cyst Wall Protein Genes in Giardia lamblia

A Novel ARID/Bright-like Protein Involved in Transcriptional Activation of Cyst Wall Protein 1 Gene in Giardia lamblia

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