AbstractsBiology & Animal Science

Overexpression of NTAP:AtCTF7¿B Leads to Pleiotropic Defects in Reproduction and Vegetative Growth in Arabidopsis

by Desheng Liu

Institution: Miami University
Department: Chemistry
Degree: PhD
Year: 2014
Keywords: Biology; Biochemistry; Cellular Biology
Record ID: 2043977
Full text PDF: http://rave.ohiolink.edu/etdc/view?acc_num=miami1416582364


Eco1/Ctf7 plays a critical role in the establishment of sister chromatid cohesion, which is required for the faithful segregation of replicated chromosomes. Inactivation of Arabidopsis CTF7 (AtCTF7) results in severe reproductive and vegetative growth defects. To further investigate potential roles of AtCTF7 and to identify AtCTF7 interacting proteins, several AtCTF7 constructs were generated and expressed in Arabidopsis plants. 35S:NTAP:AtCTF7¿B (AtCTF7¿299-345) transgenic plants displayed a wide range of phenotypic alterations in reproduction and vegetative growth. Male meiocytes from 35S:NTAP:AtCTF7¿B plants exhibited defective chromosome segregation and ultimately fragmented chromosomes. Mutant ovules developed asynchronously, experienced prolonged meiotic and megagametophytic stages and produced megaspores/embryo sacs that degenerated at various stages. The transgenic plants also exhibited a broad range of vegetative defects, including meristem disruption and apparent epigenetic alterations. Transcripts for epigenetically regulated transposable elements were elevated in transgenic plants. 35S:AtCTF7¿B transgenic plants also exhibited reduced fertility and vegetative defects, with the 35S:AtCTF7¿B defects appearing more severe than those in 35S:NTAP:AtCTF7¿B plants. Additional phenotypes were also observed in 35S:AtCTF7¿B transgenic plants. Therefore, the defects observed in 35S:NTAP:AtCTF7¿B plants are caused by high level expression of AtCTF7¿B and not the presence of the NTAP tag. Finally, Atctf7 plants containing a CTF7pro:AtCTF7¿B construct were obtained and found to grow only slightly better than Atctf7 plants. Therefore, the B motif is required for proper AtCTF7 function. In summary, this study further demonstrates that AtCTF7 plays essential roles in reproduction and in vegetative growth, and that proper levels of AtCTF7 are critical for normal plant growth and development.