Journal of Genetics and Genomics

Plant PRMTs Broaden the Scope of Arginine Methylation

Ayaz Ahmad, Xiaofeng Cao

2012, 39(5): 195-208. doi: 10.1016/j.jgg.2012.04.001

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Abstract:
Post-translational methylation at arginine residues is one of the most important covalent modifications of proteins, involved in a myriad of essential cellular processes in eukaryotes, such as transcriptional regulation, RNA processing, signal transduction, and DNA repair. Methylation at arginine residues is catalyzed by a family of enzymes called protein arginine methyltransferases (PRMTs). PRMTs have been extensively studied in various taxa and there is a growing tendency to unveil their functional importance in plants. Recent studies in plants revealed that this evolutionarily conserved family of enzymes regulates essential traits including vegetative growth, flowering time, circadian cycle, and response to high medium salinity and ABA. In this review, we highlight recent advances in the field of post-translational arginine methylation with special emphasis on the roles and future prospects of this modification in plants.

Efficient and Specific Modifications of the Drosophila Genome by Means of an Easy TALEN Strategy

Jiyong Liu, Changqing Li, Zhongsheng Yu, Peng Huang, Honggang Wu, Chuanxian Wei, Nannan Zhu, Yan Shen, Yixu Chen, Bo Zhang, Wu-Min Deng, Renjie Jiao

2012, 39(5): 209-215. doi: 10.1016/j.jgg.2012.04.003

Abstract (75) HTML PDF (0)

Abstract:
Technology development has always been one of the forces driving breakthroughs in biomedical research. Since the time of Thomas Morgan, Drosophilists have, step by step, developed powerful genetic tools for manipulating and functionally dissecting the Drosophila genome, but room for improving these technologies and developing new techniques is still large, especially today as biologists start to study systematically the functional genomics of different model organisms, including humans, in a high-throughput manner. Here, we report, for the first time inDrosophila, a rapid, easy, and highly specific method for modifying the Drosophila genome at a very high efficiency by means of an improved transcription activator-like effector nuclease (TALEN) strategy. We took advantage of the very recently developed “unit assembly” strategy to assemble two pairs of specific TALENs designed to modify the yellow gene (on the sex chromosome) and a novel autosomal gene. The mRNAs of TALENs were subsequently injected into Drosophila embryos. From 31.2% of the injected F₀ fertile flies, we detected inheritable modification involving the yellow gene. The entire process from construction of specific TALENs to detection of inheritable modifications can be accomplished within one month. The potential applications of this TALEN-mediated genome modification method in Drosophila are discussed.

A Profile of Native Integration Sites Used by φC31 Integrase in the Bovine Genome

Lijuan Qu, Qingwen Ma, Zaiwei Zhou, Haiyan Ma, Ying Huang, Shuzhen Huang, Fanyi Zeng, Yitao Zeng

2012, 39(5): 217-224. doi: 10.1016/j.jgg.2012.03.004

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Abstract:
The Streptomyces phage φC31 integrase can efficiently target attB-bearing transgenes to endogenous pseudo attP sites within mammalian genomes. To better understand the activity of φC31 integrase in the bovine genome, DNA sequences of 44 integration events were analyzed, and 32 pseudo attP sites were identified. The majority of these sites share a sequence motif that contains inverted repeats and has similarities to wild-type attP site. Genomic DNA flanking these sites typically contained repetitive sequence elements, such as short and long interspersed repetitive elements. These sequence features indicate that DNA sequence recognition plays an important role in guiding φC31-mediated site-specific integration. In addition, BF27 integration hotspot sites were identified in the bovine genome, which accounted for 13.6% of all isolated integration events and mapped to an intron of the deleted in liver cancer 1 (DLC1) gene. Also we found that the pseudo attP sites in the bovine genome had other features in common with those in the human genome. This study represents the first time that the sequence features of pseudo attP sites in the bovine genome were analyzed. We conclude that this site-specific integrase system has great potential for applied modifications of the bovine genome.

A High-Throughput Method for Screening Arabidopsis Mutants with Disordered Abiotic Stress-Induced Calcium Signal

Zhen Pan, Yang Zhao, Yuan Zheng, Juntao Liu, Xiangning Jiang, Yan Guo

2012, 39(5): 225-235. doi: 10.1016/j.jgg.2012.04.002

Abstract (85) HTML PDF (1)

Abstract:
It is established that different stresses cause signal-specific changes in cellular Ca²⁺ level, which function as messengers in modulating diverse physiological processes. These calcium signals are important for stress adaptation. Though numbers of downstream components of calcium signal cascades have been identified, upstream events in calcium signal remain elusive, specifically components required for calcium signal generation due to the lack of high-throughput genetic assay. Here, we report the development of an easy and efficient method in a forward genetic screen for Ca²⁺ signals-deficient mutants in Arabidopsis thaliana. Using this method, 121 mutants with disordered NaCl- and H₂O₂-induced Ca²⁺ signals are isolated.

2012 Vol. 39, No. 5