ABSTRACT
RNA polymerase II (Pol II) associated proteins (RPAPs) have been ascribed diverse functions at the cellular level; however, their roles in developmental processes in yeasts, animals and plants are very poorly understood. Through screening for interactors of NRPB3, which encodes the third largest subunit of Pol II, we identified RIMA, the orthologue of mammalian RPAP2. A combination of genetic and biochemical assays revealed the role of RIMA and other RPAPs in stomatal development in Arabidopsis thaliana. We show that RIMA is involved in nuclear import of NRPB3 and other Pol II subunits, and is essential for restraining division and for establishing cell identity in the stomatal cell lineage. Moreover, plant RPAPs IYO/RPAP1 and QQT1/RPAP4, which interact with RIMA, are also crucial for stomatal development. Importantly, RIMA and QQT1 bind physically to stomatal transcription factors SPEECHLESS, MUTE, FAMA and SCREAMs. The RIMA-QQT1-IYO complex could work together with key stomatal transcription factors and Pol II to drive cell fate transitions in the stomatal cell lineage. Direct interactions with stomatal transcription factors provide a novel mechanism by which RPAP proteins may control differentiation of cell types and tissues in eukaryotes.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Plant Stomata , RNA Polymerase II , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Lineage , Gene Expression Regulation, Plant , Plant Stomata/metabolism , RNA Polymerase II/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
The present article studied the fermentation liquid's absorption spectra, bacteria growth period and elastase' production in elastase fermentation, and compared and analyzed the their relation. The results show that the changes in the absorption spectra were closely related with bacteria growth and elastase' production. The UV spectroscopic technique is helpful for detecting the change of the organic nitrogen base and enzyme. The study offers a new method to detect fermentation process and is basic for detecting fermentation process on line by UV spectroscopic technique.
