Transcription initiation is controlled by three core promoter elements in the
            <i>hgl5</i>
            gene of the protozoan parasite
            <i>Entamoeba histolytica</i>

Singh, Upinder; Rogers, Joshua B.; Mann, Barbara J.; Petri, William A.

doi:10.1073/pnas.94.16.8812

Cited by 59 publications

(49 citation statements)

References 26 publications

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“…To construct pNEOCS, the NEO cassette was cloned into the SmaI site of pEhCSg1. Distances between the putative regulatory elements in the EhCS1 upstream region (38) and the initiation codon of LUC, EhCS1, or EhSAT in pNEOLUC, pNEOCS, and pNEOSAT were identical to those in the chromosomal EhCS1 locus.…”

Section: Assay Of Cs-sat Interaction Using the Yeast Two-hybridmentioning

confidence: 85%

Characterization of the Gene Encoding Serine Acetyltransferase, a Regulated Enzyme of Cysteine Biosynthesis from the Protist ParasitesEntamoeba histolyticaand Entamoeba dispar

Nozaki

Asai

Sánchez

et al. 1999

Journal of Biological Chemistry

119

113

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The enteric protist parasites Entamoeba histolytica and Entamoeba dispar possess a cysteine biosynthetic pathway, unlike their mammalian host, and are capable of de novo production of L-cysteine. We cloned and characterized cDNAs that encode the regulated enzyme serine acetyltransferase (SAT) in this pathway from these amoebae by genetic complementation of a cysteine-auxotrophic Escherichia coli strain with the amoebic cDNA libraries. The deduced amino acid sequences of the amoebic SATs exhibited, within the most conserved region, 36 -52% identities with the bacterial and plant SATs. The amoebic SATs contain a unique insertion of eight amino acids, also found in the corresponding region of a plasmid-encoded SAT from Synechococcus sp., which showed the highest overall identities to the amoebic SATs. Phylogenetic reconstruction also revealed a close kinship of the amoebic SATs with cyanobacterial SATs. Biochemical characterization of the recombinant E. histolytica SAT revealed several enzymatic features that distinguished the amoebic enzyme from the bacterial and plant enzymes: 1) inhibition by L-cysteine in a competitive manner with L-serine; 2) inhibition by Lcystine; and 3) no association with cysteine synthase. Genetically engineered amoeba strains that overproduced cysteine synthase and SAT were created. The cysteine synthase-overproducing amoebae had a higher level of cysteine synthase activity and total thiol content and revealed increased resistance to hydrogen peroxide. These results indicate that the cysteine biosynthetic pathway plays an important role in antioxidative defense of these enteric parasites.The cysteine biosynthetic pathway plays an important role in incorporation of inorganic sulfur into organic compounds. In bacteria and plants, L-cysteine is the precursor of most sulfurcontaining metabolites including methionine and glutathione. Extracellular sulfate is first imported by specific transporters. Intracellular sulfate is then activated by ATP sulfurylase and adenosine-5Ј-phosphosulfate kinase to form adenosine-5Ј-phosphosulfate and 3Ј-phosphoadenosine 5Ј-phosphosulfate, respectively. These activated sulfates are further reduced to sulfide. Sulfide then reacts with O-acetylserine, which is produced from serine and acetyl-CoA by serine acetyltransferase (SAT, 1 EC 2.3.1.30). This final reaction forming L-cysteine, by transfer of the alanyl moiety of O-acetylserine to sulfide, is catalyzed by L-cysteine synthase (CS; O-acetyl-L-serine (thiol)-lyase, EC 4.2.99.8). In contrast to bacteria and plants, animals are presumed to lack the sulfur assimilation pathway and thus require exogenous methionine as a sulfur source. Biochemical studies using purified (1-4) and recombinant enzymes (5), as well as a genetic approach using a yeast two-hybrid system, revealed that CS and SAT form a heteromeric complex. SAT activity and O-acetylserine availability are the major regulatory factors in the control of the L-cysteine production in plants (6, 7). Cytosolic isoforms of the SAT from Citrullus vulgaris and A...

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Section: Assay Of Cs-sat Interaction Using the Yeast Two-hybridmentioning

confidence: 85%

Characterization of the Gene Encoding Serine Acetyltransferase, a Regulated Enzyme of Cysteine Biosynthesis from the Protist ParasitesEntamoeba histolyticaand Entamoeba dispar

Nozaki

Asai

Sánchez

et al. 1999

Journal of Biological Chemistry

119

113

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“…The putative TATA-like motif of the GK-Xp has only slight similarity with the consensus TATA box in higher eukaryotes, however, it is similar to the TATA box found in lower eukaryotes, such as Entamoeba histolytica (sequence GTATTTAAA G / C ) (Singh et al, 1997). Furthermore, the CCAAT motif sequence ATTGG, (consensus CCAAT) is reversed, in 3' to 5' orientation.…”

Section: Gk-xp Promotermentioning

confidence: 95%

Structural and functional analysis of the promoters of the human glycerol kinase gene family

Banu¹,

M.²

2007

Afr. J. Biotechnol.

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During spermatogenesis the X-chromosome is inactivated, but several glycolytic cycle enzymes have been found to have spermatogenic cell specific isoforms encoded by the X-chromosome counterpart genes located on the autosomes. Here, the promoters of the human glycerol kinase gene family were cloned: the somatic gene called GK-Xp, and the two testis-specific isoforms called GK-1 and GK-2, using Alu-GSP primers. The structure and function of the promoters were determined by sequencing and in situ expression studies using GFP as reporter. The transcription initiation sites were mapped by RACE and, these were found at -112 for GK-Xp, -46 for GK-1, and for GK-2 at -57 nucleotide positions, upstream of the translation start codon. The GK-Xp promoter specifically contains a TATA-like motif at -26, and a CCAAT motif at -149, which are not found in either the GK-1 or GK-2 promoters. Interestingly, GK-1 contains an Inr motif, a Sp1 binding site at -11, and a DPE motif at +27 positions, whereas GK-2 contains an Inr motif, a CRE at -11, a DPE at +29 and a RARE motif at +43 positions. In addition, they both contain MEP-2 and Ets motifs, in common with other testis-specific metabolic enzymes genes, such as PGK-2 and PDHA-2.

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“…The amebic TATA (GTATTTAAA(G/C)) and Inr (AAAAATTCA) elements appear to function in a classic manner despite their sequence divergence from metazoans (9). A unique third core promoter element GAAC (GAACT) was identified in 31/37 protein-encoding E. histolytica genes (17).…”

mentioning

confidence: 99%

“…In addition, we have recently found that yeast TBP does not bind to the TATA box of the E. histolytica hgl5 gene. 2 It has been shown that amebic promoter sequences do not function in a mammalian system and that viral promoters (cytomegalovirus, human immunodeficiency virus long terminal repeat, the simian virus 40) and promoters from other systems (Dictyostelium) are nonfunctional in amebic trophozoites (8,9). Thus, it would appear that speciesspecific transcription factors may be utilized in amebic gene expression.…”

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confidence: 99%

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The Novel Core Promoter Element GAAC in the hgl5 Gene of Entamoeba histolytica Is Able to Direct a Transcription Start Site Independent of TATA or Initiator Regions

Singh

Rogers

1998

Journal of Biological Chemistry

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Entamoeba histolytica, an enteric protozoa, is the third leading parasitic cause of death worldwide. Investigation of the transcriptional machinery of this eukaryotic pathogen has revealed an unusual core promoter structure that consists of nonconsensus TATA and initiator regions and a novel third conserved core promoter sequence, the GAAC element. Mutation of this region in the hgl5 promoter decreases reporter gene expression and alters the transcription start site. Using positional analysis of this element, we have now demonstrated that it is able to direct a new transcription start site, 2-7 bases downstream of itself, independent of TATA and Inr regions. The GAAC region was also shown to control the rate of transcription via nuclear run on analysis and an amebic nuclear protein was demonstrated to specifically interact with this sequence. This is the first description in the eukaryotic literature of a third conserved core promoter element, distinct from TATA or initiator regions, that is able to direct a transcription start site. We have formulated two models for the role of the GAAC region: (i) the GAAC-binding protein is a part of the TFIID complex and (ii) the GAAC-binding protein functions to "tether" TATA-binding protein to the TATA box.

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Transcription initiation is controlled by three core promoter elements in the hgl5 gene of the protozoan parasite Entamoeba histolytica

Cited by 59 publications

References 26 publications

Characterization of the Gene Encoding Serine Acetyltransferase, a Regulated Enzyme of Cysteine Biosynthesis from the Protist ParasitesEntamoeba histolyticaand Entamoeba dispar

Characterization of the Gene Encoding Serine Acetyltransferase, a Regulated Enzyme of Cysteine Biosynthesis from the Protist ParasitesEntamoeba histolyticaand Entamoeba dispar

Structural and functional analysis of the promoters of the human glycerol kinase gene family

The Novel Core Promoter Element GAAC in the hgl5 Gene of Entamoeba histolytica Is Able to Direct a Transcription Start Site Independent of TATA or Initiator Regions

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