Multiple purine pathway enzyme activities are encoded at a single genetic locus in Drosophila.

Henikoff, Steven; Keene, Michael A.; Sloan, James S.; Bleskan, John; Hards, Robert G.; Patterson, David

doi:10.1073/pnas.83.3.720

Cited by 59 publications

(25 citation statements)

References 33 publications

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“…It is known that in eucaryotes several of these steps are catalyzed by multifunctional enzymes. A trifunctional enzyme catalyzing glycinamide ribonucleotide (GAR) synthetase, GAR transformylase, and aminoimidazole ribonucleotide (AIR) synthetase has been identified in chicken liver (14), Drosophila (17), and murine lymphoma cells (10); also identified are a bifunctional GAR synthetase-AIR synthetase in yeast cells (16), a bifunctional 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase-IMP cyclohydrolase in chicken liver (29), and a bifunctional AIR carboxylase-succino-5-aminoimidazole-4-carboxamide ribonucleotide synthetase in chicken liver (30). Furthermore, several reports support the existence of multienzyme complexes between several of the purine biosynthetic proteins.…”

Section: Discussionmentioning

confidence: 99%

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme.

Barlowe¹,

Appling²

1990

Mol. Cell. Biol.

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In eucaryotes, 10-formyltetrahydrofolate (formyl-THF) synthetase, 5,10-methenyl-THF cyclohydrolase, and NADP+-dependent 5,10-methylene-THF dehydrogenase activities are present on a single polypeptide termed C1-THF synthase. This trifunctional enzyme, encoded by the ADE3 gene in the yeast Saccharomyces cerevisiae, is thought to be responsible for the synthesis of the one-carbon donor 10-formyl-THF for de novo purine synthesis. Deletion of the ADE3 gene causes adenine auxotrophy, presumably as a result of the lack of cytoplasmic 10-formyl-THF. In this report, defined point mutations that affected one or more of the catalytic activities of yeast C1-THF synthase were generated in vitro and transferred to the chromosomal ADE3 locus by gene replacement. In contrast to ADE3 deletions, point mutations that inactivated all three activities of C1-THF synthase did not result in an adenine requirement. Heterologous expression of the Clostridium acidiurici gene encoding a monofunctional 10-formyl-THF synthetase in an ade3 deletion strain did not restore growth in the absence of adenine, even though the monofunctional synthetase was catalytically competent in vivo. These results indicate that adequate cytoplasmic 10-formyl-THF can be produced by an enzyme(s) other than C1-THF synthase, but efficient utilization of that 10-formyl-THF for purine synthesis requires a nonenzymatic function of C1-THF synthase. A monofunctional 5,10-methylene-THF dehydrogenase, dependent on NAD+ for catalysis, has been identified and purified from yeast cells (C. K. Barlowe and D. R. Appling, Biochemistry 29:7089-7094, 1990). We propose that the characteristics of strains expressing full-length but catalytically inactive C1-THF synthase could result from the formation of a purine-synthesizing multienzyme complex involving the structurally unchanged C1-THF synthase and that production of the necessary one-carbon units in these strains is accomplished by an NAD+-dependent 5,10-methylene-THF dehydrogenase.

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Section: Discussionmentioning

confidence: 99%

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme.

Barlowe¹,

Appling²

1990

Mol. Cell. Biol.

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“…Perhaps the most well-studied model for the function of the de novo purine synthesis pathway during development comes from work in Drosophila, in which mutations in prat (ppat) (Clark, 1994), ade2 (pfas) (Henikoff et al, 1986b;Johnstone et al, 1985), ade3 (gart) (Henikoff et al, 1986a;Johnstone et al, 1985) and ade5 (paics) (O'Donnell et al, 2000) have been identified, as well as mutations in the GTP pathway components IMPDH (raspberry) and GMP synthase (burgundy) (Johnstone et al, 1985;Long et al, 2006). Each of these de novo pathway mutants shows a subset of developmental defects that have collectively been termed the 'purine syndrome' phenotype (Tiong et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Zebrafish mutations ingartandpaicsidentify crucial roles for de novo purine synthesis in vertebrate pigmentation and ocular development

Uribe

Yieh

et al. 2009

Development

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Although purines and purinergic signaling are crucial for numerous biochemical and cellular processes, their functions during vertebrate embryonic development have not been well characterized. We analyze two recessive zebrafish mutations that affect de novo purine synthesis, gart and paics. gart encodes phosphoribosylglycinamide formyltransferase, phosphoribosylglycinamide synthetase, phosphoribosylaminoimidazole synthetase, a trifunctional enzyme that catalyzes steps 2, 3 and 5 of inosine monophosphate (IMP) synthesis. paics encodes phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase, a bifunctional enzyme that catalyzes steps 6 and 7 of this process. Zygotic gart and paics mutants have pigmentation defects in which xanthophore and iridophore pigmentation is almost completely absent, and melanin-derived pigmentation is significantly decreased, even though pigment cells are present in normal amounts and distributions. Zygotic gart and paics mutants are also microphthalmic, resulting from defects in cell cycle exit of proliferative retinoblasts within the developing eye. Maternal-zygotic and maternal-effect mutants demonstrate a crucial requirement for maternally derived gart and paics; these mutants show more severe developmental defects than their zygotic counterparts. Pigmentation and eye growth phenotypes in zygotic gart and paics mutants can be ascribed to separable biosynthetic pathways: pigmentation defects and microphthalmia result from deficiencies in a GTP synthesis pathway and an ATP synthesis pathway, respectively. In the absence of ATP pathway activity, S phase of proliferative retinoblasts is prolonged and cell cycle exit is compromised, which results in microphthalmia. These results demonstrate crucial maternal and zygotic requirements for de novo purine synthesis during vertebrate embryonic development, and identify independent functions for ATP and GTP pathways in mediating eye growth and pigmentation, respectively.

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“…As determined by the program TFastA, the deduced protein sequence of Tgs showed striking similarity to that of the purine biosynthesis enzyme glycinamide ribonucleotide (GAR) transformylase of Drosophila melanogaster (13) and with the corresponding purN-encoded enzyme of E. coli (36) and Bacillus subtilis (8). The protein sequences of these enzymes were aligned with the Tgs sequence (Fig.…”

Section: Jc9387mentioning

confidence: 99%

Organization and functions of genes in the upstream region of tyrT of Escherichia coli: phenotypes of mutants with partial deletion of a new gene (tgs)

Bösl

Kersten

1994

J Bacteriol

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A AiyrT::kan mutant from Escherichia coli K-12 (DTK-12) shows a transient growth lag that is caused by glycine starvation (U. Michelsen, M. Bosl, T. Dingermann, and H. Kersten, J. Bacteriol. 171:5987-5994, 1989).The same deletion, transduced into the relA spoTi mutant CA274 to construct strain DTC274, caused complete growth inhibition in glucose minimal medium. Here, we show that the tyrT 5' region contains three new open reading frames in the order 0RF37-->0RF34-*0RF32-*tyrT and that the AtyrT::kan allele used previously deletes tyrT as well as a carboxy-terminal portion of 0RF32. A plasmid encoding 0RF32 totally complemented the inability of strain DTC274 to grow on glucose minimal medium as well as the transient glycine starvation phenomenon in DTK-12, and 0RF32 was designated tgs. Partial deletion oftgs, cotransduced with the marker AlyrT::kan, was responsible for the completely different phenotypes of the deletion mutants DTK-12 and DTC274. The deduced Tgs protein sequence showed significant homology to the PurN protein of E. coli and to enzymes with glycinamide ribonucleotide transformylase activity. We discuss whether growth inhibition in strain DTC274 may be caused by synergistic effects with the preexisting mutations relA1 and spoT). The deduced protein sequence of ORF37 showed striking similarity to regulator response proteins and is probably a new member of this family. A spontaneous mutation in ORF37, caused by the integration of an insertion element, IS], exhibited no phenotype.Tyrosine-accepting tRNA is encoded by two genes in Escherichia coli, tyrT and tyrU. The tyrT operon and its regulation have been well investigated: it is under stringent control (17) and under growth rate control (40). An upstream activation sequence, including a binding site for the transactivator protein Fis (25), permits an optimal rate of transcription (16,39).The most striking feature of the tyrT operon is its structural arrangement (9,20,29,30 In a further study, this RNA, designated rtT RNA, has been identified nd characterized (3). We have made two unexpected ob ervations. (i) Plasmid-expressed rtT RNA is not only invol ed in complementation of the glycine starvation in the AtyrT:: an strain DTK-12 but also influences growth arrest induced b isoleucine deprivation. Therefore, a general modulatory ro e of rtT RNA upon stringent control that is not restricted to glycine starvation in strain has been suggested. (ii) The extent of growth delay in the AtyrT::kan strain DTK-12 is increased under more-limiting conditions with glycerol as carbon source. Under these conditions, the characteristic lag phase in strain DTK-12 has been only partially o ercome by the tyrT operon, probably because of the modulato effect of rtT RNA upon stringent control, indicating that de etion of the tyrT operon is not or at least is not the only genetic cause for the phenomenon of transient glycine starvation, designated the tyrT deletion phenotype (22).In the stl dy presented here, the hypothesis that a second site mutation i involved in genera...

show abstract

Multiple purine pathway enzyme activities are encoded at a single genetic locus in Drosophila.

Cited by 59 publications

References 33 publications

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme.

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme.

Zebrafish mutations ingartandpaicsidentify crucial roles for de novo purine synthesis in vertebrate pigmentation and ocular development

Organization and functions of genes in the upstream region of tyrT of Escherichia coli: phenotypes of mutants with partial deletion of a new gene (tgs)

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