The RIN-MC fusion of MADS-box transcription factors has transcriptional activity.

5 years ago

The RIN-MC fusion of MADS-box transcription factors has transcriptional activity.

Zheng Ju, Huijinlan Xu, Benzhong Zhu, Yunbo Luo, Donald Grierson, Dongyan Cao, Daqi Fu, Hongliang Zhu, Guozheng Qin, Shan Li

Fruit development and ripening is regulated by genetic and environmental factors and is of critical importance for seed dispersal, reproduction and fruit quality. Tomato rin mutant fruit have a classic ripening-inhibited phenotype, which is attributed to a genomic DNA deletion resulting in the fusion of two truncated transcription factors, RIN and MC. In wild-type fruit, RIN, a MADS-box transcription factor, is a key regulator of the ripening gene expression network with hundreds of gene targets controlling changes in color, flavor, texture and taste during tomato fruit ripening; MC, on the other hand, has low expression in fruit, and the potential functions of the RIN-MC fusion gene in ripening remain unclear. Here, over-expression of RIN-MC in transgenic wild-type AC tomato fruits impaired several ripening processes, and down-regulating RIN-MC expression in the rin mutant was found to stimulate the normal yellow mutant fruit to produce a weak red color, suggesting a distinct negative role for RIN-MC in tomato fruit ripening. By comparative transcriptome analysis of rin and rin 35S::RIN-MC RNAi fruits, a total of 1168 and 1234 genes were identified as potential targets of RIN-MC activation and inhibition. Further, the RIN-MC fusion gene was shown to be translated into a chimeric transcription factor that was localized to the nucleus and was capable of protein interactions with other MADS-box factors. These results indicated that RIN-MC is functional and controls expression of many ripening genes, thereby contributing to the rin mutant phenotype.

Publisher URL: http://doi.org/10.1104/pp.17.01449

DOI: 10.1104/pp.17.01449