Molecular cloning and cytochemical analysis of exopolygalacturonase from carrot.
Exopolygalacturonase (exo-PGase, EC 3.2.1.67) attacks the non-reducing terminus of the polygalacturonic acid in pectic molecules, releasing galacturonic acid. We cloned the cDNA of exo-PGase purified from cell homogenates of suspension-cultured carrot ( Daucus carota L. cv. Kintoki) cells. The nucleotide sequence of the cDNA (1.4 kb) contains an open reading frame that encodes a 391-amino-acid polypeptide. Sequence homology research showed 97.9% identity to the glycoprotein EP4 obtained from cultured carrot cells and 49.3% identity to the ENOD8 gene product of alfalfa ( Medicago sativa). However, no significant similarity was found to known PGases. The Southern hybridization pattern indicated that this exo-PGase protein is a member of a small-sized gene family. Predominant expression of the exo-PGase gene was detected by in situ hybridization and immunohistochemistry in the root apical meristem and in the elongation region, but not in the root cap. A cross-immunoresponse with anti-exo-PGase also occurred in the root nodule meristem of alfalfa. These results suggest that this exo-PGase plays a role in the degradation of pectic molecules during root development.
Tanaka
Reiji
R
Aburahi Laboratories, Shionogi & Co., Ltd., Gotanda, Koka, Shiga, Japan. reiji.tanaka@shionogi.co.jp
Ikeda
Minoru
M
Funatsuki
Kenzo
K
Yukioka
Hideo
H
Hashimoto
Yutaka
Y
Fujimoto
Shigeyoshi
S
Takata
Masaru
M
Katoh
Kenji
K
Konno
Haruyoshi
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D018552:Daucus carota / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D018519:Meristem / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D010368:Pectins / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D018744:DNA, Plant; D006603:Hexuronic Acids; C007819:galacturonic acid; D010368:Pectins; D006026:Glycoside Hydrolases; C020136:exopolygalacturonase; C003181:polygalacturonic acid