Structure and expression of MdFBCP1, encoding an F-box-containing protein 1, during Fuji apple (Malus domestica Borkh.) fruit ripening.
From database comparisons of 1,117 expressed sequence tags (ESTs) generated from ripened Fuji apple fruits, we identified ten ubiquitin (Ub)-related genes. RNA gel-blot analysis suggests that these Ub-related genes are induced by at least four distinct signaling pathways in fruits. In this study, we analyzed structure and expression of MdFBCP1, encoding an F-box-containing protein 1, in Fuji apples. MdFBCP1 transcript was predominantly expressed in the fully ripened climacteric fruits, in which serge of ethylene production occurred. The MdFBCP1 gene was also activated effectively in response to exogenous ethylene treatment, with the induction pattern being comparable to those of ACC oxidase and beta-cyanoalanine synthase. Thus, it seems likely that the expression of MdFBCP1 is closely associated with a climacteric ethylene production and ACC oxidase activity and, hence, MdFBCP1 may play a role in the ripening process of Fuji apple fruits. Yeast two hybrid and in vitro pull-down assays revealed that MdFBCP1 physically interacted with MdSkp1 and N-terminal F-box motif was essential for this interaction. These results suggest that MdFBCP1 indeed functions as an F-box-containing protein and participates in the formation of SCF complex, which acts as E3 Ub ligase. Genomic Southern blot analysis showed that MdFBCP1 exhibited different pattern of restriction enzyme digestion in three cultivars (Tsugaru, Golden Delicious and Fuji) that produce different amount of ethylene, suggesting that the MdFBCP1 gene is organized in a cultivar specific manner. Collectively, our data suggest that Ub degradation pathway may play an important role in the ripening of Fuji apple fruits.
Han
Sang Eun
SE
Department of Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-749, South Korea.
Seo
Young Sam
YS
Heo
Seong
S
Kim
Daeil
D
Sung
Soon-Kee
SK
Kim
Woo Taek
WT
D000595:Amino Acid Sequence; D015139:Blotting, Southern; D005030:Ethylenes / Q000494:pharmacology; D020224:Expressed Sequence Tags; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
D005030:Ethylenes; D044783:F-Box Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C036216:ethylene