title: Characterization of an ethylene-inducible, calcium-dependent nuclease that is differentially expressed in cucumber flower development.
abstract: • Production of unisexual flowers is an important mechanism that promotes cross-pollination in angiosperms. We previously identified primordial anther-specific DNA damage and organ-specific ethylene perception responsible for the arrest of stamen development in female flowers, but little is known about how the two processes are linked. • To identify potential links between the two processes, we performed suppression subtractive hybridization (SSH) on cucumber (Cucumis sativus L.) stamens of male and female flowers at stage 6, with stamens at stage 5 of bisexual flowers as a control. • Among the differentially expressed genes, we identified an expressed sequence tag (EST) encoding a cucumber homolog to an Arabidopsis calcium-dependent nuclease (CAN), designated CsCaN. Full-length CsCaN cDNA and the respective genomic DNA sequence were cloned and characterized. The CsCaN protein exhibited calcium-dependent nuclease activity. CsCaN showed ubiquitous expression; however, increased gene expression was detected in the stamens of stage 6 female flowers compared with male flowers. As expected, CsCaN expression was ethylene inducible. It was of great interest that CsCaN was post-translationally modified. • This study demonstrated that CsCaN is a novel cucumber nuclease gene, whose DNase activity is regulated at multiple levels, and which could be involved in the primordial anther-specific DNA damage of developing female cucumber flowers.
authors.affiliation: PKU-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Gu
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Chao-Xing
authors.initials: CX
authors.lastname: He
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Xu
authors.forename: Shu-Nong
authors.initials: SN
authors.lastname: Bai
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D003001:Cloning, Molecular; D018553:Cucumis sativus / Q000166:cytology / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D018076:DNA, Complementary / Q000235:genetics; D003851:Deoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D005030:Ethylenes / Q000494:pharmacology*; D035264:Flowers / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D005030:Ethylenes; D007527:Isoenzymes; D010940:Plant Proteins; C036216:ethylene; D003851:Deoxyribonucleases; D002118:Calcium