Characterization of the Common Bean Uricase II and Its Expression in Organs Other than Nodules

Abstract

Uricase II is a purine metabolic enzyme highly induced in root nodules during the symbiosis established between legumes and bacteria of the genera Rhizobium and Bradyrhizobium. Here we describe the characterization of bean (Phaseolus vulgaris) nodule uricase II cDNA and show that uricase I I is encoded by a single gene in the bean genome. This gene is also expressed in cotyledons, roots, and hypocotyls during bean seedling establishment, and an antiuricase antibody recognizes the protein in different seedling organs. Uricase II has also been found in leucaena leucocephala seedlings, suggesting that it participates during seedling establishment in legumes that do not transport ureides. A 50-kD polypeptide that is detected by the anti-uricase antibody is found in cotyledons during seedling development. This higher-molecular-mass form is also detected in developing roots and hypocotyls but not in nodules. In situ hybridization experiments in root seedlings showed uricase II transcripts in the metaxylem parenchyma cells and phloem fibers of the vascular system.

Structural and genomic organization, cDNA characterization and expression analysis of the urate oxidase gene from chickpea (Cicer arietinum)†

“…The deduced chickpea uricase protein carries the invariable copper motif (HEHGF) present in all plant uricases (Wu et al 1989) except for the common bean (HQHGF) (Papadopoulou et al 1995, Capote‐Maínez and Sánchez 1997). Three other motifs are also present in the chickpea uricase protein.…”

“…Our Southern blot analysis strongly suggests that a single copy uricase gene is present in the chickpea genome. Only one gene has also been described in common bean (Capote‐Maínez and Sánchez 1997), while two uricase genes seem to be present in soybean (Takane et al 1997b). The genomic organization of the chickpea gene is remarkably similar to that of the soybean gene, the only uricase genomic sequence so far published (Nguyen et al 1985, Takane et al 1997b).…”

“…The non‐symbiotic GAAGAG motif, which is characteristic of non‐symbiotic haemoglobin gene promoters (Andersson et al 1997), and also present in the soybean uricase UR2 gene promoter (Takane et al 1997b), is not present in the 5′‐ flanking region of the chickpea uricase gene, reinforcing the idea that the chickpea uricase gene is a symbiotic gene. However, symbiotic uricase genes are expressed in other non‐symbiotic tissues (Capote‐Maínez and Sánchez 1997, Takane et al 1997b). Accordingly, the chickpea uricase gene is expressed in nodules, roots and aerial parts (shoot and leaves) of the plant (Fig.…”

“…The gene encoding uricase has already been cloned and studied at the molecular level in plants such as soybean (Bergmann et al 1983, Nguyen et al 1985, Kouchi et al 1989, Takane et al 1997b), common bean (Sánchez et al 1987, Papadopoulou et al 1995, Capote‐Maínez and Sánchez 1997), mothbean ( Vigna aconitifolia L.) (Lee et al 1993), and jackbean ( Canavalia ensiformis L.) (Kim and An 1993). However, little is known about its regulatory mechanisms (Nguyen et al 1985, Sánchez et al 1987, Tajima et al 1991, Lee et al 1993).…”

Urate oxidase

“…<1> Homo sapiens [1] <2> Oryctolagus cuniculus [2,38] <3> Candida utilis [3,10,13,14,40,47,49] <4> Rattus norvegicus [4,23,25,42,57] <5> Sus scrofa [5, 14, 24, 27-30, 33, 57] <6> Bos taurus [31][32][33][34][35][36][37] <7> Phaseolus vulgaris [6,60,61] <8> Drosophila melanogaster [7] <9> Streptomyces aureofaciens [8] <10> Glycine max (inoculated with Bradyrhizobium japonicum [9]; thioredoxin fusion protein [55,58]) [9,12,51,55,58] <11> Bacillus fastidiosus [11,20,21,22,47,56] <12> Vigna unguiculata [16] <13> Streptomyces cyanogenus [15] <14> Enterobacter cloacae [17] <15> Aspergillus flavus [18,47,<...>…”