Light-modulated abundance of an mRNA encoding a calmodulin-regulated, chromatin-associated NTPase in pea

Hsieh, Hsu-Liang; Tong, Chii-Gong; Thomas, C. George; Roux, Stanley J.

doi:10.1007/bf00017808

Cited by 57 publications

(69 citation statements)

References 35 publications

(39 reference statements)

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“…A search of protein and nucleotide databases using the NCB1 TBLASTN and BLASTN programs (23) showed no significant similarities of LNP to the amino acid or cDNA sequences of any other plant or animal lectin yet described. It did, however, show 65.6% and 47.6% amino acid identity and 70.7% and 58.7% nucleotide identity with the sequences of a pea nucleotide triphosphatase (24) and an apyrase isolated from potato tubers (25), respectively. Considerably less, but significant, similarity also was found with the sequences of several other animal and yeast phosphohydrolases.…”

Section: Resultsmentioning

confidence: 99%

A nod factor binding lectin with apyrase activity from legume roots

Kalsi

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

151

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A lectin isolated from the roots of the legume, Dolichos biflorus, binds to Nod factors produced by rhizobial strains that nodulate this plant and has a deduced amino acid sequence with no significant homology to any lectin reported to date. This lectin also is an enzyme that catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside di-and triphosphates; the enzyme activity is increased in the presence of carbohydrate ligands. This lectin-nucleotide phosphohydrolase (LNP) has a substrate specificity characteristic of the apyrase category of phosphohydrolases, and its sequence contains four motifs characteristic of this category of enzymes. LNP is present on the surface of the root hairs, and treatment of roots with antiserum to LNP inhibits their ability to undergo root hair deformation and to form nodules on exposure to rhizobia. These properties suggest that this protein may play a role in the rhizobium-legume symbiosis and/or in a related carbohydrate recognition event endogenous to the plant.Oligosaccharide signaling events play important roles in the regulation of plant development, defense, and other interactions of plants with the environment (1-4). The establishment of the nitrogen-fixing symbiotic relationship between rhizobia and leguminous plants depends on such a signaling process. The rhizobia produce lipochitooligosaccharidic signals, called Nod factors, that elicit the differentiation of a new organ, the nodule, in the root cortex. The rhizobia bind to and invade the root hairs, where they proceed to the emerging nodule within infection threads produced by the plant (5). Both the initiation of nodule formation and rhizobial entry are host-strainspecific; this specificity is determined by the type of Nod factor produced by a particular rhizobial strain and by the ability of a leguminous species to recognize that signal.All Nod factors consist of a short, typically tetrapentameric, chitin oligosaccharidic backbone that is N-acylated at the nonreducing end, usually with a common fatty acid, such as cis-vaccenic acid. The Nod factors differ from one another in length of this backbone and the type of substituents that decorate it; these modifications determine the strain specificity of the rhizobium and depend on the set of nodulation genes possessed by that rhizobial strain (4). A related set of signals are the chitin oligosaccharides, themselves, that have been found to elicit defense responses in a wide variety of plants (for review, see ref.3).Although the structures of many of these chitooligosaccharides have been characterized, little is known about the plant proteins that bind these signals, whether as receptors for signal transduction or as binding proteins with other functions. High-affinity binding sites for chitin fragments have been found on membranous fractions prepared from tomato (7) and rice (8) suspension-cultured cells, and a 70-kDa protein that binds to chitin fragments was isolated from the rice membranes (9). Particulate fractions from roots of the legume, Medicago t...

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Section: Resultsmentioning

confidence: 99%

A nod factor binding lectin with apyrase activity from legume roots

Kalsi

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

151

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“…This enzyme requires activation by Ca 2ϩ -bound calmodulin to convert Glu to ␥-aminobutyric acid, which is rapidly accumulated in nodules in response to various stresses (Ling et al, 1994;Serraj et al, 1998). Apyrase, another enzyme known for its calmodulin-binding properties (Hsieh et al, 1996), has also been reported to play an essential role in plant-rhizobium symbiosis (Cohn et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

Genome-Wide Identification of Nodule-Specific Transcripts in the Model Legume Medicago truncatula

et al. 2002

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The Medicago truncatula expressed sequence tag (EST) database (Gene Index) contains over 140,000 sequences from 30 cDNA libraries. This resource offers the possibility of identifying previously uncharacterized genes and assessing the frequency and tissue specificity of their expression in silico. Because M. truncatula forms symbiotic root nodules, unlike Arabidopsis, this is a particularly important approach in investigating genes specific to nodule development and function in legumes. Our analyses have revealed 340 putative gene products, or tentative consensus sequences (TCs), expressed solely in root nodules. These TCs were represented by two to 379 ESTs. Of these TCs, 3% appear to encode novel proteins, 57% encode proteins with a weak similarity to the GenBank accessions, and 40% encode proteins with strong similarity to the known proteins. Nodule-specific TCs were grouped into nine categories based on the predicted function of their protein products. Besides previously characterized nodulins, other examples of highly abundant nodule-specific transcripts include plantacyanin, agglutinin, embryo-specific protein, and purine permease. Six nodule-specific TCs encode calmodulin-like proteins that possess a unique cleavable transit sequence potentially targeting the protein into the peribacteroid space. Surprisingly, 114 nodule-specific TCs encode small Cys cluster proteins with a cleavable transit peptide. To determine the validity of the in silico analysis, expression of 91 putative nodule-specific TCs was analyzed by macroarray and RNA-blot hybridizations. Nodule-enhanced expression was confirmed experimentally for the TCs composed of five or more ESTs, whereas the results for those TCs containing fewer ESTs were variable. , and organ development (Ruan et al., 1998;Girke et al., 2000; Zhu and Wang, 2000). Although Arabidopsis serves as the model system for most plant processes, it suffers from two major weaknesses in consideration of plant-microbe interactions: the absence of symbiotic associations with mycorrhizal fungi and with rhizobia.In recent years, Medicago truncatula and Lotus japonicus have emerged as model systems for genomic approaches to plant-microbe symbiotic associations (Barker et al., 1990;Handberg and Stougaard, 1992; Cook et al., 1997; Cook, 1999;Oldroyd and Geurts, 2001;Thoquet et al., 2002). Both species possess small genomes, are diploid, have fast generation times, and can be transformed with Agrobacterium tumefaciens and regenerated (Handberg and Stougaard, 1992; Blondon et al., 1994;Handberg et al., 1994; Chabaud et al., 1996;Jiang and Gresshoff, 1997;Stiller et al., 1997;Trinh et al., 1998;Trieu et al., 2000). Currently, both functional and structural genomics approaches are being pursued within each of these species. Covitz et al. (1998) reported the sequencing of about 900 cDNA tags from the M. truncatula root hairs. In addition, hundreds more expressed sequence tags (ESTs) have been isolated and characterized from effective root nodules of L. japonicus and M. truncatula, and a ...

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“…The NH 2 -terminal 445-amino acid hydrophilic segment of Apy1p contains the apyrase domain. The apyrase domains of other E-ATPases are all located extracellularly, through either a cleaved (6,8,9) or a noncleaved signal sequence (5,14,17). Surprisingly, there is no signal sequence in the NH 2 -terminal portion of Apy1p; in addition, this domain (445 amino acids) is much larger than the extracellular domain of known type III membrane proteins (Ͻ100 amino acids) (51).…”

Section: Cloning Of the Apy1 Gene From Yeast Chromosomal Dna-mentioning

confidence: 99%

“…The molecular identity of the E-ATPases was revealed recently by the purification and cloning of a soluble apyrase from potato tubers (Solanum tuberosum) (6). The deduced amino acid sequence for potato apyrase had sequence similarities with various other polypeptides in the data base, including CD39, a human and mouse lymphoid cell antigen (7), garden pea NTPase (8), and Toxoplasma gondii NTPase (9). All of these proteins contain four highly conserved sequences called apyrase conserved regions (ACR1-4).…”

mentioning

confidence: 99%