bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cloning and Functional Analysis of cDNAs with Open Reading Frames for 300 Previously Undefined Genes Expressed in CD34+ Hematopoietic Stem/Progenitor Cells
Authors: Zhang Qing-Hua , Ye Min , Wu Xin-Yan , Ren Shuang-Xi , Zhao Meng , Zhao Chun-Jun , Fu Gang , Shen Yu , Fan Hui-Yong , Lu Gang , Zhong Ming , Xu Xiang-Ru , Han Ze-Guang , Zhang Ji-Wang , Tao Jiong , Huang Qiu-Hua , Zhou Jun , Hu Geng-Xi , Gu Jian , Chen Sai-Juan , Chen Zhu 
Published: July 2002

Three hundred cDNAs containing putatively entire open reading frames (ORFs) for previously undefined genes were obtained from CD34+ hematopoietic stem/progenitor cells (HSPCs), based on EST cataloging, clone sequencing, in silico cloning, and rapid amplification of cDNA ends (RACE). The cDNA sizes ranged from 360 to 3496 bp and their ORFs coded for peptides of 58–752 amino acids. Public database search indicated that 225 cDNAs exhibited sequence similarities to genes identified across a variety of species. Homology analysis led to the recognition of 50 basic structural motifs/domains among these cDNAs. Genomic exon–intron organization could be established in 243 genes by integration of cDNA data with genome sequence information. Interestingly, a new gene named as HSPC070 on 3p was found to share a sequence of 105bp in 3′ UTR with RAF gene in reversed transcription orientation. Chromosomal localizations were obtained using electronic mapping for 192 genes and with radiation hybrid (RH) for 38 genes. Macroarray technique was applied to screen the gene expression patterns in five hematopoietic cell lines (NB4, HL60, U937, K562, and Jurkat) and a number of genes with differential expression were found. The resource work has provided a wide range of information useful not only for expression genomics and annotation of genomic DNA sequence, but also for further research on the function of genes involved in hematopoietic development and differentiation.[The sequence data described in this paper have been submitted to the GenBank data library under the accession nos. listed in Table 1, pp 1548–1552.]
Interaction of the Arabidopsis E2F and DP Proteins Confers Their Concomitant Nuclear Translocation and Transactivation
Authors: Kosugi Shunichi , Ohashi Yuko 
Published: July 2002

Abstract
E2F transcription factors are required for the progression and arrest of the cell cycle in animals. Like animals, plants have evolved to conserve the E2F family. The Arabidopsis genome encodes E2F and DP proteins that share a high similarity with the animal E2F and DP families. Here, we show that Arabidopsis E2F and DP proteins are not predominantly localized to the nucleus in analyses with green fluorescent protein, and that the complete nuclear localization of some members is driven by the co-expression of their specific partner proteins. Both AtE2F1 and AtE2F3 were translocated to the nucleus and transactivate an E2F reporter gene when co-expressed with DPa but not DPb. In contrast, AtE2F2 was inactive for both nuclear translocation and transactivation even when Dpa or DPb was co-expressed. Because the DNA binding activities of the three E2Fs are equally stimulated by the interaction with DPa or DPb in vitro, the observed transactivation of AtE2F1 and AtE2F3 is DPa specific and nuclear import dependent. A green fluorescent protein fusion with an AtE2F3 mutant, in which a conserved nuclear export signal-like sequence in the dimerization domain was deleted, was localized to the nucleus. Thus, the concomitant nuclear translocation seems to be conferred by the DPa interaction to release an activity that inhibits an intrinsic nuclear import activity of AtE2Fs. Furthermore, the nuclear translocation of AtE2F3 stimulated by DPa was abolished by the deletion of the N-terminal region of AtE2F3, which is conserved among all the E2F proteins identified in plants to date. Replacement of the N-terminal region of AtE2F3 with a canonical nuclear localization signal only partially mimicked the effect of the DPa co-expression, demonstrating the function of plant E2F distinct from that observed for animal E2Fs. These observations suggest that the function of plant E2F and DP proteins is primarily controlled by their nuclear localization mediated by the interaction with specific partner proteins.
Gibberellin Produced in the Cotyledon Is Required for Cell Division during Tissue Reunion in the Cortex of Cut Cucumber and Tomato Hypocotyls
Authors: Asahina Masashi , Iwai Hiroaki , Kikuchi Akira , Yamaguchi Shinjiro , Kamiya Yuji , Kamada Hiroshi , Satoh Shinobu 
Published: July 2002

Abstract
Cucumber (Cucumis sativus) hypocotyls were cut to one-half of their diameter transversely, and morphological and histochemical analyses of the process of tissue reunion in the cortex were performed. Cell division in the cortex commenced 3 d after cutting, and the cortex was nearly fully united within 7 d. 4′,6-Diamidino-2-phenylindole staining and 5-bromo-2′-deoxyuridine labeling experiments indicate that nDNA synthesis occurred during this process. In addition, specific accumulation of pectic substances was observed in the cell wall of attached cells in the reunion region of the cortex. Cell division during tissue reunion was strongly inhibited when the cotyledon was removed. This inhibition was reversed by applying gibberellin (GA, 10−4 mGA3) to the apical tip of the cotyledon-less plant. Supporting this observation, cell division in the cortex was inhibited by treatment of the cotyledon with 10−4 municonazole-P (an inhibitor of GA biosynthesis), and this inhibition was also reversed by simultaneous application of GA. In contrast to the essential role of cotyledon, normal tissue reunion in cut hypocotyls was still observed when the shoot apex was removed. The requirement of GA for tissue reunion in cut hypocotyls was also evident in the GA-deficient gib-1 mutant of tomato (Lycopersicon esculentum). Our results suggest that GA, possibly produced in cotyledons, is essential for cell division in reuniting cortex of cut hypocotyls.
Pollen-Stigma Adhesion in Kale Is Not Dependent on the Self-(In)Compatibility Genotype
Authors: Luu D. T. , Heizmann P. , Dumas C. 
Published: July 2002

Abstract
The adhesion of pollen on the stigmas of flowering plants is a critical step for the success of reproduction in angiosperms, long considered to present some specificity in terms of self-incompatibility. We carried out quantitative measurements of the pollen-stigma adhesion (expressed in Newtons) in kale (Brassica oleracea), using the flotation force of Archimedes exerted by dense sucrose solutions (50%, w/v) to release pollen grains fixed on the surface of stigmas. We demonstrate that pollen adhesion varies with the genotypes of the plants used as partners, but increases with time in all cases for about 30 to 60 min after pollination. There is no correlation with the self- or cross-status of the pollinations, nor with the self-compatible or -incompatible genotypes of the parents. Only late events of pollination, after the germination or arrest of the pollen tube, depend on compatibility type. Biochemical and physiological dissection of pollen-stigma adhesion points to major components of this interaction: among male components, the pollen coating, eliminated by delipidation (or modified by mutation in the case of the cer mutants of the related species Arabidopsis thaliana), plays a major role in adhesion; the genetic background of the pollen parent is also of some importance. On the female side, the developmental stage of the stigma and the protein constituents of the stigmatic pellicle are critical for pollen capture. The SLG and SLR1 proteins are not involved in the initial stages of pollen adhesion on the stigma but one or both may be involved in the later stages.
The COW1 Locus of Arabidopsis Acts after RHD2, and in Parallel with RHD3 and TIP1, to Determine the Shape, Rate of Elongation, and Number of Root Hairs Produced from Each Site of Hair Formation
Authors: Grierson C. S. , Roberts K. , Feldmann K. A. , Dolan L. 
Published: July 2002

Abstract
Two recessive mutant alleles at CAN OF WORMS1 (COW1), a new locus involved in root hair morphogenesis, have been identified in Arabidopsis thaliana L. Heynh. Root hairs on Cow1- mutants are short and wide and occasionally formed as pairs at a single site of hair formation. The COW1 locus maps to chromosome 4. Root hairs on Cow1- plants form in the usual positions, suggesting that the phenotype is not the result of abnormal positional signals. Root hairs on Cowl- roots begin hair formation normally, forming a small bulge, or root hair initiation site, of normal size and shape and in the usual position on the hair-forming cell. However, when Cow1- root hairs start to elongate by tip growth, abnormalities in the shape and elongation rate of the hairs become apparent. Genetic evidence from double-mutant analysis of cow1–1 and other loci involved in root hair development supports our conclusion that COW1 is required during root hair elongation.
Nucleotide Triphosphates Are Required for the Transport of Glycolate Oxidase into Peroxisomes1
Authors: Brickner Donna G. , Olsen Laura J. 
Published: July 2002

Abstract
All peroxisomal proteins are nuclear encoded, synthesized on free cytosolic ribosomes, and posttranslationally targeted to the organelle. We have used an in vitro assay to reconstitute protein import into pumpkin (Cucurbita pepo) glyoxysomes, a class of peroxisome found in the cotyledons of oilseed plants, to study the mechanisms involved in protein transport across peroxisome membranes. Results indicate that ATP hydrolysis is required for protein import into peroxisomes; nonhydrolyzable analogs of ATP could not substitute for this requirement. Nucleotide competition studies suggest that there may be a nucleotide binding site on a component of the translocation machinery. Peroxisomal protein import also was supported by GTP hydrolysis. Nonhydrolyzable analogs of GTP did not substitute in this process. Experiments to determine the cation specificity of the nucleotide requirement show that the Mg2+ salt was preferred over other divalent and monovalent cations. The role of a putative protonmotive force across the peroxisomal membrane was also examined. Although low concentrations of ionophores had no effect on protein import, relatively high concentrations of all ionophores tested consistently reduced the level of protein import by approximately 50%. This result suggests that a protonmotive force is not absolutely required for peroxisomal protein import.
Evidence for 1-(Malonylamino)cyclopropane-1-Carboxylic Acid Being the Major Conjugate of Aminocyclopropane-1-Carboxylic Acid in Tomato Fruit1
Authors: Peiser Galen , Fa Yang Shang 
Published: July 2002

AbstractTomato (Lycopersicon esculentum Miller) fruit discs fed with [2,3-14C]1-aminocyclopropane-1-carboxylic acid (ACC) formed 1-malonyl-ACC (MACC) as the major conjugate of ACC in fruit throughout all ripening stages, from immature-green through the red-ripe stage. Another conjugate of ACC, γ-glutamyl-ACC (GACC), was formed only in mature-green fruit in an amount about 10% of that of MACC; conjugation of ACC into GACC was not detected in fruits at other ripening stages. No GACC formation was observed from etiolated mung bean (Vigna radiata [L.] Wilczek) hypocotyls, etiolated common vetch (Vicia sativum L.) epicotyls, or pea (Pisum sativum L.) root tips, etiolated epicotyls, and green stem tissue, where active conversion of ACC into MACC was observed. GACC was, however, formed in vitro in extracts from fruit of all ripening stages. GACC formation in an extract from red fruit at pH 7.15 was only about 3% of that at pH 8.0, the pH at which most assays were run. Our present in vivo data support the previous contention that MACC is the major conjugate of ACC in plant tissues, whereas GACC is a minor, if any, conjugate of ACC. Thus, our data do not support the proposal that GACC formation could be more important than MACC formation in tomato fruit.
Differential Regulation of Sugar-Sensitive Sucrose Synthases by Hypoxia and Anoxia Indicate Complementary Transcriptional and Posttranscriptional Responses1
Authors: Zeng Ying , Wu Yong , Avigne Wayne T. , Koch Karen E. 
Published: July 2002

Abstract
The goal of this research was to resolve the hypoxic and anoxic responses of maize (Zea mays) sucrose (Suc) synthases known to differ in their sugar regulation. The two maize Suc synthase genes, Sus1 andSh1, both respond to sugar and O2, and recent work suggests commonalities between these signaling systems. Maize seedlings (NK508 hybrid, W22 inbred, and an isogenicsh1-null mutant) were exposed to anoxic, hypoxic, and aerobic conditions (0, 3, and 21% O2, respectively), when primary roots had reached approximately 5 cm. One-centimeter tips were excised for analysis during the 48-h treatments. At the mRNA level,Sus1 was rapidly up-regulated by hypoxia (approximately 5-fold in 6 h), whereas anoxia had less effect. In contrast,Sh1 mRNA abundance increased strongly under anoxia (approximately 5-fold in 24 h) and was much less affected by hypoxia. At the enzyme level, total Suc synthase activity rose rapidly under hypoxia but showed little significant change during anoxia. The contributions of SUS1 and SH1 activities to these responses were dissected over time by comparing the sh1-null mutant with the isogenic wild type (Sus+, Sh1+).Sh1-dependent activity contributed most markedly to a rapid protein-level response consistently observed in the first 3 h, and, subsequently, to a long-term change mediated at the level of mRNA accumulation at 48 h. A complementary midterm rise in SUS1 activity varied in duration with genetic background. These data highlight the involvement of distinctly different genes and probable signal mechanisms under hypoxia and anoxia, and together with earlier work, show parallel induction of “feast and famine” Suc synthase genes by hypoxia and anoxia, respectively. In addition, complementary modes of transcriptional and posttranscriptional regulation are implicated by these data, and provide a mechanism for sequential contributions from the Sus1 and Sh1 genes during progressive onset of naturally occurring low-O2events.
Dimethylsulfoniopropionate Biosynthesis inSpartina alterniflora1
Authors: Kocsis Michael G. , Nolte Kurt D. , Rhodes David , Shen Tun-Li , Gage Douglas A. , Hanson Andrew D. 
Published: July 2002

Abstract
The osmoprotectant 3-dimethylsulfoniopropionate (DMSP) occurs in Gramineae and Compositae, but its synthesis has been studied only in the latter. The DMSP synthesis pathway was therefore investigated in the salt marsh grassSpartina alterniflora Loisel. Leaf tissue metabolized supplied [35S]methionine (Met) toS-methyl-l-Met (SMM), 3-dimethylsulfoniopropylamine (DMSP-amine), and DMSP. The35S-labeling kinetics of SMM and DMSP-amine indicated that they were intermediates and, consistent with this, the dimethylsulfonium moiety of SMM was shown by stable isotope labeling to be incorporated as a unit into DMSP. The identity of DMSP-amine, a novel natural product, was confirmed by both chemical and mass-spectral methods. S. alterniflora readily converted supplied [35S]SMM to DMSP-amine and DMSP, and also readily converted supplied [35S]DMSP-amine to DMSP; grasses that lack DMSP did neither. A small amount of label was detected in 3-dimethylsulfoniopropionaldehyde (DMSP-ald) when [35S]SMM or [35S]DMSP-amine was given. These results are consistent with the operation of the pathway Met → SMM → DMSP-amine → DMSP-ald → DMSP, which differs from that found in Compositae by the presence of a free DMSP-amine intermediate. This dissimilarity suggests that DMSP synthesis evolved independently in Gramineae and Compositae.
High Aluminum Resistance in Buckwheat1
Authors: Ma Jian Feng , Hiradate Syuntaro , Matsumoto Hideaki 
Published: July 2002

Abstract
Buckwheat (Fagopyrum esculentum Moench. cv Jianxi), which shows high Al resistance, accumulates Al in the leaves. The internal detoxification mechanism was studied by purifying and identifying Al complexes in the leaves and roots. About 90% of Al accumulated in the leaves was found in the cell sap, in which the dominant organic acid was oxalic acid. Purification of the Al complex in the cell sap of leaves by molecular-sieve chromatography resulted in a complex with a ratio of Al to oxalic acid of 1:3. A 13C-nuclear magnetic resonance study of the purified cell sap revealed only one signal at a chemical shift 164.4 ppm, which was assigned to the Al-chelated carboxylic group of oxalic acid. A 27Al-nuclear magnetic resonance analysis revealed one major signal at the chemical shift of 16.0 to 17.0 ppm, with a minor signal at the chemical shift of 11.0 to 12 ppm in both the intact roots and their cell sap, which is consistent with the Al-oxalate complexes at 1:3 and 1:2 ratios, respectively. The purified cell sap was not phytotoxic to root elongation in corn (Zea mays). All of these results indicate that Al tolerance in the roots and leaves of buckwheat is achieved by the formation of a nonphytotoxic Al-oxalate (1:3) complex.
Molecular Characterization of an Arabidopsis Gene Encoding Hydroperoxide Lyase, a Cytochrome P-450 That Is Wound Inducible1
Authors: Bate Nicholas J. , Sivasankar Sobhana , Moxon Claire , Riley John M.C. , Thompson John E. , Rothstein Steven J. 
Published: July 2002

Abstract
Hydroperoxide lyase (HPL) cleaves lipid hydroperoxides to produce volatile flavor molecules and also potential signal molecules. We have characterized a gene from Arabidopsis that is homologous to a recently cloned HPL from green pepper (Capsicum annuum). The deduced protein sequence indicates that this gene encodes a cytochrome P-450 with a structure similar to that of allene oxide synthase. The gene was cloned into an expression vector and expressed in Escherichia coli to demonstrate HPL activity. Significant HPL activity was evident when 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid was used as the substrate, whereas activity with 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid was approximately 10-fold lower. Analysis of headspace volatiles by gas chromatography-mass spectrometry, after addition of the substrate to E. coli extracts expressing the protein, confirmed enzyme-activity data, since cis-3-hexenal was produced by the enzymatic activity of the encoded protein, whereas hexanal production was limited. Molecular characterization of this gene indicates that it is expressed at high levels in floral tissue and is wound inducible but, unlike allene oxide synthase, it is not induced by treatment with methyl jasmonate.
A Steep Dependence of Inward-Rectifying Potassium Channels on Cytosolic Free Calcium Concentration Increase Evoked by Hyperpolarization in Guard Cells1
Authors: Grabov Alexander , Blatt Michael R. 
Published: July 2002

Abstract
Inactivation of inward-rectifying K+ channels (IK,in) by a rise in cytosolic free [Ca2+] ([Ca2+]i) is a key event leading to solute loss from guard cells and stomatal closure. However, [Ca2+]i action onIK,in has never been quantified, nor are its origins well understood. We used membrane voltage to manipulate [Ca2+]i (A. Grabov and M.R. Blatt [1998] Proc Natl Acad Sci USA 95: 4778–4783) while recordingIK,in under a voltage clamp and [Ca2+]i by Fura-2 fluorescence ratiophotometry. IK,in inactivation correlated positively with [Ca2+]i and indicated a Ki of 329 ± 31 nm with cooperative binding of four Ca2+ ions per channel. IK,in was promoted by the Ca2+ channel antagonists Gd3+ and calcicludine, both of which suppressed the [Ca2+]i rise, but the [Ca2+]i rise was unaffected by the K+ channel blocker Cs+. We also found that ryanodine, an antagonist of intracellular Ca2+ channels that mediate Ca2+-induced Ca2+ release, blocked the [Ca2+]i rise, and Mn2+quenching of Fura-2 fluorescence showed that membrane hyperpolarization triggered divalent release from intracellular stores. These and additional results point to a high signal gain in [Ca2+]i control ofIK,in and to roles for discrete Ca2+ flux pathways in feedback control of the K+ channels by membrane voltage.
NADH-Glutamate Synthase in Alfalfa Root Nodules. Genetic Regulation and Cellular Expression1
Authors: Trepp Gian B. , van de Mortel Martijn , Yoshioka Hirofumi , Miller Susan S. , Samac Deborah A. , Gantt J. Stephen , Vance Carroll P. 
Published: July 2002

Abstract
NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) is a key enzyme in primary nitrogen assimilation in alfalfa (Medicago sativa L.) root nodules. Here we report that in alfalfa, a single gene, probably with multiple alleles, encodes for NADH-GOGAT. In situ hybridizations were performed to assess the location of NADH-GOGAT transcript in alfalfa root nodules. In wild-type cv Saranac nodules theNADH-GOGAT gene is predominantly expressed in infected cells. Nodules devoid of bacteroids (empty) induced bySinorhizobium meliloti 7154 had no NADH-GOGAT transcript detectable by in situ hybridization, suggesting that the presence of the bacteroid may be important for NADH-GOGAT expression. The pattern of expression of NADH-GOGAT shifted during root nodule development. Until d 9 after planting, all infected cells appeared to express NADH-GOGAT. By d 19, a gradient of expression from high in the early symbiotic zone to low in the late symbiotic zone was observed. In 33-d-old nodules expression was seen in only a few cell layers in the early symbiotic zone. This pattern of expression was also observed for the nifH transcript but not for leghemoglobin. The promoter of NADH-GOGAT was evaluated in transgenic alfalfa plants carrying chimeric β-glucuronidase promoter fusions. The results suggest that there are at least four regulatory elements. The region responsible for expression in the infected cell zone contains an 88-bp direct repeat.
Slow and Prolonged Activation of the p47 Protein Kinase during Hypersensitive Cell Death in a Culture of Tobacco Cells
Authors: Suzuki Kaoru , Yano Akira , Shinshi Hideaki 
Published: July 2002

Abstract
To investigate the involvement of protein kinases in the signaling cascade that leads to hypersensitive cell death, we used a previously established system in which a fungal elicitor, xylanase from Trichoderma viride (TvX), induces a hypersensitive reaction in tobacco (Nicotiana tabacum) cells in culture (line XD6S). The elicitor induced the slow and prolonged activation of a p47 protein kinase, which has the characteristics of a family member of the mitogen-activated protein kinases. An inhibitor of protein kinases, staurosporine, and a blocker of Ca channels, Gd3+ ions, both of which blocked the TvX-induced hypersensitive cell death, inhibited the TvX-induced activation of p47 protein kinase. Moreover, an inhibitor of serine/threonine protein phosphatase alone induced both rapid cell death and the persistent activation of the p47 protein kinase. Thus, the p47 protein kinase might be a component of the signal transduction pathway that leads to hypersensitive cell death, and the regulation of the duration of activation of the p47 protein kinase might be important in determining the destiny of tobacco cells.