TY - JOUR
T1 - Upstream elements required for expression of nucleoside triphosphate hydrolase genes of Toxoplasma gondii
AU - Nakaar, Valerian
AU - Bermudes, David
AU - Peck, Kyong Ran
AU - Joiner, Keith A.
N1 - Funding Information:
We are grateful to John Boothroyd, Stanford University, Palo Alto for kindly providing pTUB5/CAT and pTUB- β gal. We thank Christian Tschudi and Tim Stedman for critical comments on the manuscript. This investigation was supported by a Public Health Service Grant AI 31808 (to K.A.J.) and by Samsung Medical Center, Seoul, South Korea (K.R.P.). K.A.J. is a Burroughs Wellcome Fund Scholar in Molecular Parasitology.
PY - 1998/5/1
Y1 - 1998/5/1
N2 - Nucleoside triphosphate hydrolase is an abundant protein secreted by the obligate protozoan parasite Toxoplasma gondii. The protein has apyrase activity, degrading ATP to the di- and mono-phosphate forms. Because T. gondii is incapable of de novo synthesis of purines, it is postulated that NTPase may be used by the parasite to salvage purines from the host cell for survival and replication. To elucidate the molecular mechanisms of NTP gene expression, we isolated from the virulent RH strain of T. gondii the putative promoter region of three tandemly repeated NTP genes (NTP1, 2, 3). Using deletion constructs linked to the chloramphenicol acetyl transferase (CAT) reporter gene, we defined an active promoter within the first 220 bp. Sequence analysis of this region reveals the lack of a TATA box, but the promoter region is associated with a sequence which resembles an initiator element (Inr) in the NTP1 and NTP3 genes. This sequence which is similar to other Inrs known to regulate the expression of a wide variety of RNA polymerase II genes, is required for NTP expression. The NTP3 promoter contains sufficient information for developmentally regulated expression of CAT activity when the actively replicating stage tachyzoite differentiates into the dormant bradyzoite form. Copyright (C) 1998 Elsevier Science B.V.
AB - Nucleoside triphosphate hydrolase is an abundant protein secreted by the obligate protozoan parasite Toxoplasma gondii. The protein has apyrase activity, degrading ATP to the di- and mono-phosphate forms. Because T. gondii is incapable of de novo synthesis of purines, it is postulated that NTPase may be used by the parasite to salvage purines from the host cell for survival and replication. To elucidate the molecular mechanisms of NTP gene expression, we isolated from the virulent RH strain of T. gondii the putative promoter region of three tandemly repeated NTP genes (NTP1, 2, 3). Using deletion constructs linked to the chloramphenicol acetyl transferase (CAT) reporter gene, we defined an active promoter within the first 220 bp. Sequence analysis of this region reveals the lack of a TATA box, but the promoter region is associated with a sequence which resembles an initiator element (Inr) in the NTP1 and NTP3 genes. This sequence which is similar to other Inrs known to regulate the expression of a wide variety of RNA polymerase II genes, is required for NTP expression. The NTP3 promoter contains sufficient information for developmentally regulated expression of CAT activity when the actively replicating stage tachyzoite differentiates into the dormant bradyzoite form. Copyright (C) 1998 Elsevier Science B.V.
KW - Nucleoside triphoshate hydrolase cis-elements
KW - Regulation
KW - Toxoplasma gondii
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U2 - 10.1016/S0166-6851(97)00220-X
DO - 10.1016/S0166-6851(97)00220-X
M3 - Article
C2 - 9657328
AN - SCOPUS:0010370623
VL - 92
SP - 229
EP - 239
JO - Molecular and Biochemical Parasitology
JF - Molecular and Biochemical Parasitology
SN - 0166-6851
IS - 2
ER -