Journal of Genetics and Genomics

Cytoplasmic Poly(A) Binding Protein 4 Is Highly Expressed in Human Colorectal Cancer and Correlates with Better Prognosis

Dan Liu, Bin Yin, Qiang Wang, Wenyi Ju, Yuanjia Chen, Huizhong Qiu, Ji Li, Xiaozhong Peng, Chongmei Lu

2012, 39(8): 369-374. doi: 10.1016/j.jgg.2012.05.007

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Abstract:
Cytoplasmic poly(A) binding protein 4 (PABPC4) is an RNA-processing protein that plays an important role in the regulation of gene expression. The aim of this study was to investigate the expression pattern and identify the potential clinical significance of PABPC4 in colorectal cancer. Immunohistochemical analysis revealed that 26.7% (27/101 patients) of primary colorectal tumors and 60.5% (23/38 patients) of corresponding adjacent, normal tissues showed high cytoplasmic expression of PABPC4, whereas expression was absent in 98% (43/44 patients) of distant, normal tissues. Using Kaplan–Meier analysis, we observed that the expression of PABPC4 was significantly correlated with disease-free survival and overall survival in patients with stage II and stage III colorectal cancer (P=0.022 and P=0.020, respectively). PABPC4 expression was positively associated with survival outcome, and may have predictive value in the prognosis of patients with colorectal cancer. Taken together, our findings indicate that PABPC4 may play a role in the pathogenesis of colorectal cancer.

Butyrate-induced GPR41 Activation Inhibits Histone Acetylation and Cell Growth

Jin Wu, Zongli Zhou, Yinghe Hu, Suzhen Dong

2012, 39(8): 375-384. doi: 10.1016/j.jgg.2012.05.008

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Abstract:
Butyrate has been recently identified as a natural ligand of the G-protein-coupled receptor 41 (GPR41). In addition, it is an inhibitor of histone deacetylase (HDAC). Butyrate treatment results in the hyperacetylation of histones, with resultant multiple biological effects including inhibition of proliferation, induction of cell cycle arrest, and apoptosis, in a variety of cultured mammalian cells. However, it is not clear whether GPR41 is actively involved in the above-mentioned processes. In this study, we generated a stable cell line expressing the hGPR41 receptor in order to investigate the involvement of GPR41 on butyrate-induced biochemical and physiologic processes. We found that GPR41 activation may be a compensatory mechanism to counter the increase in histone H3 acetylation levels induced by butyrate treatment. Moreover, GPR41 had an inhibitory effect on the anti-proliferative, pro-apoptotic effects of butyrate. GPR41 expression induced cell cycle arrest at the G1-stage, while its activation by butyrate can cause more cells to pass the G1 checkpoint. These results indicated that GPR41 was associated with histone acetylation and might be involved in the acetylation-related regulation of cell processes including proliferation, apoptosis, and the cell cycle.

Characterization and Fine Mapping of a Novel Rice Albino Mutant low temperature albino 1

Yu Peng, Yi Zhang, Jun Lv, Jianhui Zhang, Ping Li, Xiaoliang Shi, Yufeng Wang, Honglei Zhang, Zuhua He, Sheng Teng

2012, 39(8): 385-396. doi: 10.1016/j.jgg.2012.05.001

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Abstract:
Albino mutants are useful genetic resource for studying chlorophyll biosynthesis and chloroplast development and cloning genes involved in these processes in plants. Here we report a novel rice mutant low temperature albino 1 (lta1) that showed albino leaves before 4-leaf stage when grown under temperature lower than 20°C, but developed normal green leaves under temperature higher than 24°C or similar morphological phenotypes in dark as did the wild-type (WT). Our analysis showed that the contents of chlorophylls and chlorophyll precursors were remarkably decreased in the lta1 mutant under low temperature compared to WT. Transmission electron microscope observation revealed that chloroplasts were defectively developed in the albino lta1 leaves, which lacked of well-stacked granum and contained less stroma lamellae. These results suggested that the lta1 mutation may delay the light-induced thylakoid assembly under low temperature. Genetic analysis indicated that the albino phenotype was controlled by a single recessive locus. Through map-based approach, we finally located theLta1 gene to a region of 40.3 kb on the short arm of chromosome 11. There are 8 predicted open reading frames (ORFs) in this region and two of them were deleted in lta1 genome compared with the WT genome. The further characterization of the Lta1 gene would provide a good approach to uncover the novel molecular mechanisms involved in chloroplast development under low temperature stress.

A Systematic Phenotypic Screen of F-box Genes Through a Tissue-specific RNAi-based Approach in Drosophila

Wen Dui, Wei Lu, Jun Ma, Renjie Jiao

2012, 39(8): 397-413. doi: 10.1016/j.jgg.2012.05.009

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Abstract:
F-box proteins are components of the SCF (SkpA-Cullin 1-F-box) E3 ligase complexes, acting as the specificity-determinants in targeting substrate proteins for ubiquitination and degradation. In humans, at least 22 out of 75 F-box proteins have experimentally documented substrates, whereas in Drosophila 12 F-box proteins have been characterized with known substrates. To systematically investigate the genetic and molecular functions of F-box proteins in Drosophila, we performed a survey of the literature and databases. We identified 45 Drosophila genes that encode proteins containing at least one F-box domain. We collected publically available RNAi lines against these genes and used them in a tissue-specific RNAi-based phenotypic screen. Here, we present our systematic phenotypic dataset from the eye, the wing and the notum. This dataset is the first of its kind and represents a useful resource for future studies of the molecular and genetic functions of F-box genes in Drosophila. Our results show that, as expected, F-box genes in Drosophila have regulatory roles in a diverse array of processes including cell proliferation, cell growth, signal transduction, and cellular and animal survival.

UBC32 Mediated Oxidative Tolerance in Arabidopsis

Feng Cui, Lijing Liu, Qingliang Li, Chengwei Yang, Qi Xie

2012, 39(8): 415-417. doi: 10.1016/j.jgg.2012.05.005

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Abstract:

2012 Vol. 39, No. 8