title: Proline responding1 Plays a Critical Role in Regulating General Protein Synthesis and the Cell Cycle in Maize.
abstract: Proline, an important amino acid, accumulates in many plant species. Besides its role in plant cell responses to environmental stresses, the potential biological functions of proline in growth and development are unclear. Here, we report cloning and functional characterization of the maize (Zea mays) classic mutant proline responding1 (pro1) gene. This gene encodes a Δ1-pyrroline-5- carboxylate synthetase that catalyzes the biosynthesis of proline from glutamic acid. Loss of function of Pro1 significantly inhibits proline biosynthesis and decreases its accumulation in the pro1 mutant. Proline deficiency results in an increased level of uncharged tRNApro AGGaccumulation and triggers the phosphorylation of eukaryotic initiation factor 2α (eIF2α) in the pro1 mutant, leading to a general reduction in protein synthesis in this mutant. Proline deficiency also downregulates major cyclin genes at the transcriptional level, causing cell cycle arrest and suppression of cell proliferation. These processes are reversible when external proline is supplied to the mutant, suggesting that proline plays a regulatory role in the cell cycle transition. Together, the results demonstrate that proline plays an important role in the regulation of general protein synthesis and the cell cycle transition in plants.
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China Coordinated Crop Biology Research Center, Beijing 100193, P.R. China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Jushan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China Coordinated Crop Biology Research Center, Beijing 100193, P.R. China.
authors.forename: Guifeng
authors.initials: G
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Fan
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Qin
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Zhong
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Qiao
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China.
authors.forename: Yuanping
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China Coordinated Crop Biology Research Center, Beijing 100193, P.R. China rentaosong@staff.shu.edu.cn.
authors.forename: Rentao
authors.initials: R
authors.lastname: Song