Evidence for Subfunctionalization of the Flip4 Gene Family in Arabidopsis Thaliana

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Michael Judge (Creator)
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/
Annkatrin Rose

Abstract: Gene duplication events are thought to be major drivers of diversity in angiosperm lineages. For most duplicated genes, one paralog is quickly lost to fractionation or pseudogenization. Alternatively, random mutations in one or both paralogs sometimes allow them to develop new or specialized roles. We hypothesize a current shift from redundancy to subfunctionalization between the paralogs AtFLIP4-1 and AtFLIP4-2 (Filament-like Protein 4), two genes coding for uncharacterized coiled-coil proteins in Arabidopsis thaliana. Phenotypes differ for single knock-out mutants (flip4-1 plants are sickly with low fertility; flip4-2 plants are indistinguishable from the wild-type). Furthermore, FLIP4-1 is highly expressed in sperm and pollen while localization of FLIP4-2 to the chloroplast has been observed in green protoplast culture. On the other hand, double knock-out mutants appear to be inviable, suggesting a redundant and vital FLIP4 function. To explore potential genetic interactions between the genes and their product functions, reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to quantify the expression of both genes throughout the development of the plant in the different mutants. Furthermore, network analysis tools were used to explore their potential functions. Both genes were expressed at relatively low levels in most leaf and reproductive organ tissues, while FLIP4-2 appeared to be upregulated late in leaf development and in buds and siliques. The expression profiles of the two paralogs were not found to correlate with each other well, and their interaction partners differ, suggesting subfunctionalization. Furthermore, the expression pattern of FLIP4-2 is consistent with a role in senescence or stress responses.

Additional Information

Honors Project
Judge, M.T. (2015). Evidence for Subfunctionalization of the Flip4 Gene Family in Arabidopsis Thaliana. Unpublished honors thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2015
FLIP4, Gene duplication, arabidopsis thaliana, coiled protein, gene expression, RT-aPC2

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