A Meristem-Related Gene from Tomato Encodes a dUTPase: Analysis of Expression in Vegetative and Floral Meristems

Pri-Hadash, Aviva; Hareven, Dana; Lifschitz, Eliezer

doi:10.2307/3869568

Cited by 9 publications

(12 citation statements)

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“…At least four to five layers of apical cells were labeled, indicating that cells in all apical meristematic layers (LI, LII, and LIII) express TM5 and TM6. Provascular cells, which at this stage already express the dUTPase gene (Pri-Hadash et al, 1992), were not yet labeled, but were extensively marked during organogenesis (Figures 2A to 2D).…”

Section: Resultsmentioning

confidence: 97%

“…We examined the earliest possible stage of localized TM5 and TM6 gene expression by probing sections of wild-type and ananfha floral meristems at the preorganogenesis stage with labeled TM5 or TM6 antisense RNA. Meristematic organs of the ananfha mutant inflorescences are arrested at the preorganogenesis stage (Helm, 1951) and exhibit patterns of gene expression characteristic of floral primordia (Shahar et al, 1992;Pri-Hadash et al, 1992). Localization of TM5 RNA in the early preorganization stage of wild-type floral buds is shown in Figure lA, and localization of TM6 RNA in early wild-type floral buds and in ananfha floral meristems is depicted in Figures 18 and 1C.…”

Section: Resultsmentioning

confidence: 99%

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The TM5 MADS Box Gene Mediates Organ Differentiation in the Three Inner Whorls of Tomato Flowers.

et al. 1994

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The tomato MADS box gene no. 5 (TM5) is shown here to be expressed in meristematic domains fated to form the three inner whorls-petals, stamens, and gynoecia-of the tomato flower. TM5 is also expressed during organogenesis and in the respective mature organs of these three whorls. This is unlike the major organ identity genes of the MADS box family from Antirrhinum and Arabidopsis, which function in overlapping primordial territories consisting of only two floral whorls each. The developmental relevance of the unique expression pattern of this putative homeotic gene was examined in transgenic plants. In agreement with the expression patterns, antisense RNA of the TM5 gene conferred both early and late alterations of morphogenetic markers. Early defects consist of additional whorls or of a wrong number of organs per whorl. Late, organ-specific changes include evergreen, cauline, and unabscised petals; green, dialytic, and sterile anthers; and sterile carpels and defective styles on which glandular trichomes characteristic of sepals and petals are ectopically formed. However, a complete homeotic transformation of either organ was not observed. The early and late floral phenotypes of TM5 antisense plants suggest that TM5 mediates two unrelated secondary regulatory systems. One system is the early function of the floral meristem identity genes, and the other system is the function of the major floral organ identity genes.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

The TM5 MADS Box Gene Mediates Organ Differentiation in the Three Inner Whorls of Tomato Flowers.

et al. 1994

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“…Studies of dUTPase in plants suggest that expression is linked to the rate of proliferation, as demonstrated by a close association of dUTPase activity and replicative vegetative and floral meristem regions (16,17). Recently, the dUTPase gene was isolated from the human fungal pathogen, Candida albicans, the expression of which is governed in part by an MluI cell cycle box element located in the promoter region (18).…”

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confidence: 99%

The Human dUTPase Gene Encodes both Nuclear and Mitochondrial Isoforms

Ladner

Caradonna

1997

Journal of Biological Chemistry

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We have previously identified distinct nuclear and mitochondrial isoforms of dUTPase in human cells, reporting the cDNA sequence of the nuclear isoform (DUT-N). We now report a cDNA corresponding to the mitochondrial isoform (DUT- dUTPase (EC 3.6.1.23) catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate, simultaneously removing dUTP from the DNA biosynthetic pathway and providing substrate (dUMP) for the de novo synthesis of thymidylate (1). The importance of the dUTPase function in prokaryotic, eukaryotic, and viral systems has been firmly established in recent years. dUTPase is essential for viability in Escherichia coli and Saccharomyces cerevisiae and was shown to be required for efficient DNA replication in several viral systems (2-5). The importance of the dUTPase function in the human system has been further distinguished by its importance in anti-thymidylate chemotherapy.MThymidylate metabolism has been an important target for the development of widely utilized chemotherapeutic agents such as 5-fluorouracil, fluorodeoxyuridine, and ZD1694 that are used in the treatment of breast and gastrointestinal tumors. The enzymatic target of these compounds, thymidylate synthase (TS), 1 generates dTMP from dUMP and a folate cofactor. Investigations by several laboratories suggest that the basis of cytotoxicity caused by inhibition of de novo thymidylate metabolism may be the accumulation of excessive dUTP pools (6 -9). TS inhibition induces a dramatic elevation of dUTP pools resulting in chronic dUMP misincorporation into DNA during replication and repair, leading to DNA fragmentation and cell death (7). Work published by Curtin et al. (7) demonstrates a significant correlation between intracellular dUTP levels and the magnitude of DNA damage resulting from TS inhibition. dUTPase (the major regulator of dUTP pools in humans) plays a protective role by limiting dUTP accumulation in the cell and countering the cytotoxic effect of TS inhibition. Recently, direct evidence supporting this role was demonstrated. Overexpression of the E. coli dUTPase in HT29 human colorectal tumor cells resulted in the induction of resistance to the TS inhibitor fluorodeoxyuridine (10). These studies provide substantial evidence suggesting that levels of the dUTPase enzyme may be a critical factor in determining fluorodeoxyuridine toxicity in certain cancer types. The essential nature of dUTPase during

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“…A growing number of dUTPases from various sources have been reported and several sequences have been published (Bj6rnberg et al, 1993;Bergman et al, 1994: Elder et al, 1992Broyles, 1993;Roseman et al, 1996;Giroir & Deutsch, 1987;Climie et al, 1994;McIntosh et a/., 1992McIntosh et a/., , 1994Pri-Hadash et al, 1992;Wagaman et al, 1993). Protein sequence comparisons between the E. coli enzyme (Lundberg, Thoresson et al, 1983) and viral dUTPases (McGeoch, 1990) revealed five conserved motifs scattered along the sequence, indicating that those parts might be important for catalytic function and/or stability.…”

Section: Introductionmentioning

confidence: 99%

The Refined Structure of dUTPase from Escherichia coli

Dauter¹,

Wilson²,

Larsson³

et al. 1998

Acta Cryst D

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Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase, E.C. 3.6.1.23) catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate and is involved in nucleotide metabolism and DNA synthesis. A crystal of the recombinant E. coli enzyme, precipitated from polyethylene glycol mixtures in the presence of succinate at pH 4.2, was used to collect synchrotron diffraction data to 1.9 A resolution, in space group R3, a = b = 86.62, c = 62.23 A. Mercury and platinum derivative data were collected at wavelengths to optimize the anomalous contribution. The resulting 2.2 A MIRAS phases differed from the final set by 40 c on average and produced an excellent map which was easy to interpret. The model contains 132 water molecules and refined to an R value of 13.7%. 136 residues have clear electron density out of 152 expected from the gene sequence. The 16 C-terminal residues are presumably disordered in the crystal lattice. The monomer is a 'jelly-roll' type, containing mostly/3-sheet and only one short helix. The molecule is a tight trimer. A long C-terminal arm extends from one subunit and encompasses the next one within the trimer contributing to its fl-sheet. Conserved sequence motifs common among dUTPases, previously suggested to compose the active site and confirmed in a recent study of the dUDP complex, are located at subunit-subunit interfaces along the threefold axis, in parts of the fl-sheet and in loop regions. A similar molecular architecture has recently been found in two other trimeric dUTPases.

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A Meristem-Related Gene from Tomato Encodes a dUTPase: Analysis of Expression in Vegetative and Floral Meristems

Cited by 9 publications

References 0 publications

The TM5 MADS Box Gene Mediates Organ Differentiation in the Three Inner Whorls of Tomato Flowers.

The TM5 MADS Box Gene Mediates Organ Differentiation in the Three Inner Whorls of Tomato Flowers.

The Human dUTPase Gene Encodes both Nuclear and Mitochondrial Isoforms

The Refined Structure of dUTPase from Escherichia coli

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