科研之友
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摘要
The inducible CO2 concentratingmechanism(CCM) ofmicroalgae is essential for their acclimation to highly variable aquatic inorganic carbon levels. The key transcriptional regulator, CIA5, affects expression of thousands of genes in Chlamydomonas reinhardtii, but themolecular characteristics of this important protein are poorly understood. This study identifies a functional activation domain in CIA5 and demonstrates the functionality of a miniCIA5 including only the zinc-binding domain and the identified activation domain. A highly conserved 130aa region fromCIA5 exhibits auto-activation in yeast and appears responsible for themarkedly slow migration of CIA5 when analyzed by SDS-PAGE. This 130aa region or either half of this region also effectively replaced the activation domain of a modified designer Transcription Activator-like Element (dTALE) in targeted activation of an endogenous Chlamydomonas gene. Additionally, a mini-CIA5 combining the conserved zinc-binding domain with the 130aa putative activation domain complemented the growth phenotype of the cia5 mutant and triggered CO2-regulated gene expression patterns similar to wild-type cells or cia5 complemented with the full-length CIA5. Although the mini-CIA5 complementation did not fully restore wild-type growth rates or full gene induction/ repression amplitudes, especially in very low CO2, this newly identified activation domain combined with the previously described zinc-binding domain are demonstrated to be the key essential components of CIA5 that permit rapid CIA5-mediated responses to changes in CO2 concentrations.
- 出版日期2017-6
- 单位华中农业大学; 农业微生物学国家重点实验室
