Search

The role of a fertilization signal in controlling apoptosis of extra-embryonic cells, using thyroxine (T4)-dependent NF- [kappa]B pathway during embryonic development of Ciona intestinalis, is studied.

Author(s): Cyrille de Joussineau; Jonathan Soulé [2]; Marianne Martin [2]; Christelle Anguille; Philippe Montcourrier; Daniel Alexandre (corresponding author) Drosophila thoracic mechanosensory bristles originate from cells that are singled out from [...]

Sequence analysis of the 8-kb genomic DNA fragment that complements the syrA phenotype revealed high conservation among a broad spectrum of fluorescent pseudomonads. The results demonstrate that the syrA locus is the argA gene of P. syrinage pv. syrinage and that argA are directly involved in arginine biosynthesis and therefore indirectly affect syringomycin production because of arginine deficiency.

Author(s): Cyrille de Joussineau; Jonathan Soulé; Marianne Martin; Christelle Anguille; Philippe Montcourrier; Daniel Alexandre Nature 426, 555-559 (2003). In the authors' published address, 'UMR 5539' should read 'CNRS UMR 5539'. [...]

Two types of necrosis-inducing lipodepsipeptide toxins, called syringomycin and syringopeptin, are major virulence factors of Pseudomonas syringae pv. syringae strain B301D. A previous study showed that a locus, called syrA, was required for both syringomycin production and plant pathogenicity, and the syrA locus was speculated to encode a regulator of toxin production. In this study, sequence analysis of the 8-kb genomic DNA fragment that complements the syrA phenotype revealed high conservation among a broad spectrum of fluorescent pseudomonads. The putative protein encoded by open reading frame 4 (ORF4) (1,299 bp) in the syrA locus region exhibited 85% identity to ArgA, which is involved in arginine biosynthesis in Pseudomonas aeruginosa. Growth of strain W4S2545, the syrA mutant, required supplementation of N minimal medium with arginine. Similarly, syringomycin production of syrA mutant W4S2545 was restored by the addition of arginine to culture media. Furthermore, the insertion of Tn5 in the genome of the syrA mutant W4S2545 was localized between nucleotides 146 and 147 in ORF4, and syringomycin production was complemented in trans with the wild-type DNA fragment containing intact ORF4. These results demonstrate that the syrA locus is the argA gene of P. syringae pv. syringae and that argA is directly involved in arginine biosynthesis and therefore indirectly affects syringomycin production because of arginine deficiency.