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Proteomic analysis of rice embryo: An approach for investigating Gα protein‐regulated proteins
Author(s) -
Komatsu Setsuko,
Abbasi Fida,
Kobori Eiko,
Fujisawa Yukiko,
Kato Hisaharu,
Iwasaki Yukimoto
Publication year - 2005
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200401237
Subject(s) - mutant , heterotrimeric g protein , biology , wild type , microbiology and biotechnology , abscisic acid , embryo , proteome , protein subunit , g protein , biochemistry , signal transduction , gene
The rice dwarf1 ( d1 ) mutant, which lacks the α subunit of a heterotrimeric G protein (Gα protein), shows abnormal morphology due to shortened internodes, dark green leaves and grains that are small and round. Proteome analysis was used in this study to aid in determining the function of Gα protein in rice embryos. Using 2‐DE, seven seed embryo proteins were shown to be down‐regulated in the d1 mutant as compared with its wild type. These seven proteins included a receptor for activated C‐kinase (RACK) and six rice embryo globulin‐2 proteins (REG2). The six REG2 have similar molecular masses with minor differences in p I . In addition to the reduced accumulation of RACK in the d1 mutant, the increase in QL/ d1, in which a constitutively active form of the Gα protein is expressed, was significantly higher as compared with wild type. The level of accumulation of these seven proteins during seed development and maturation did not change significantly until the 2nd wk after pollination. Reduced accumulation of these seven proteins started in the d1 mutant at the 3rd wk after pollination, and continued until seed maturation was complete. All seven proteins were completely absent 24 h after imbibition in both d1 mutant and its wild type. However, the phytohormone abscisic acid promoted the expression level of RACK after imbibition in the wild type as compared with d1 mutant. These results suggest that RACK is regulated by Gα‐protein and plays an important role in a basic cellular process as well as in rice embryogenesis and germination.