A vacuolar processing enzyme, deltaVPE, is involved in seed coat formation at the early stage of seed development.
Vacuolar processing enzyme (VPE) is a Cys proteinase responsible for the maturation of vacuolar proteins. Arabidopsis thaliana deltaVPE, which was recently found in the database, was specifically and transiently expressed in two cell layers of the seed coat (ii2 and ii3) at an early stage of seed development. At this stage, cell death accompanying cell shrinkage occurs in the ii2 layer followed by cell death in the ii3 layer. In a deltaVPE-deficient mutant, cell death of the two layers of the seed coat was delayed. Immunocytochemical analysis localized deltaVPE to electron-dense structures inside and outside the walls of seed coat cells that undergo cell death. Interestingly, deltaVPE in the precipitate fraction from young siliques exhibits caspase-1-like activity, which has been detected in various types of plant cell death. Our results suggest that, at the early stage of seed development, deltaVPE is involved in cell death of limited cell layers, the purpose of which is to form a seed coat.
Nakaune
Satoru
S
Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Yamada
Kenji
K
Kondo
Maki
M
Kato
Tomohiko
T
Tabata
Satoshi
S
Nishimura
Mikio
M
Hara-Nishimura
Ikuko
I
D017360:Arabidopsis / Q000196:embryology* / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D020170:Caspase 1 / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008854:Microscopy, Electron; D010802:Phylogeny; D012639:Seeds / Q000166:cytology / Q000201:enzymology / Q000254:growth & development
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D003546:Cysteine Endopeptidases; C472134:seed-type vacuolar processing enzyme delta, Arabidopsis; D020170:Caspase 1