The Calmodulin-Binding Protein IQM1 Interacts with CATALASE2 to Affect Pathogen Defense.

Calmodulin (CaM) regulates plant disease responses through its downstream calmodulin-binding proteins (CaMBPs) often by affecting the biosynthesis or signaling of phytohormones, such as jasmonic acid (JA) and salicylic acid. However, how these CaMBPs mediate plant hormones and other stress resistance-related signaling remains largely unknown. In this study, we conducted analyses in Arabidopsis (Arabidopsis thaliana) on the functions of AtIQM1 (IQ-Motif Containing Protein1), a Ca2+-independent CaMBP, in JA biosynthesis and defense against the necrotrophic pathogen Botrytis cinerea using molecular, biochemical, and genetic analyses. IQM1 directly interacted with and promoted CATALASE2 (CAT2) expression and CAT2 enzyme activity and indirectly increased the activity of the JA biosynthetic enzymes ACX2 and ACX3 through CAT2, thereby positively regulating JA content and B. cinerea resistance. In addition, in vitro assays showed that in the presence of CaM5, IQM1 further enhanced the activity of CAT2, suggesting that CaM5 may affect the activity of CAT2 by combining with IQM1 in the absence of Ca2+ Our data indicate that IQM1 is a key regulatory factor in signaling of plant disease responses mediated by JA. The study also provides new insights that CaMBP may play a critical role in the cross talk of multiple signaling pathways in the context of plant defense processes.

PFKFB4 negatively regulated the expression of histone acetyltransferase GCN5 to mediate the tumorigenesis of thyroid cancer.

Thyroid cancer (TC) is the most common malignant endocrine tumor, and its incidence has progressively increased over several decades. Accumulating evidence has suggested that PFKFB4, a critical regulatory enzyme of glycolysis, has been implicated in various solid cancers. However, the exact effect of PFKFB4 on TC remains unclear. Hence, the objective of this work was to investigate the role of PFKFB4 in TC and explore the underlying regulatory mechanisms. Here, we provide evidence that mRNA levels of PFKFB4 were upregulated in TC patients' thyroids and cell lines. Downregulation of PFKFB4 reduced TC cell viability and inhibited colony formation. In addition, the migration and invasion of TC cells were suppressed by PFKFB4 knockdown, suggesting that PFKFB4 is positively correlated with tumorigenesis of TC. Molecularly, knockdown of PFKFB4 significantly inhibited expression of GCN5 and phosphorylation of PI3K/AKT. Moreover, the suppressive role of shPFKFB4 in TC cell growth was reversed by upregulation of GCN5. Finally, the in vivo experiment indicated that downregulation of PFKF4B suppressed tumor growth in xenografts TC model mice. In total, our results suggested that PFKFB4-mediated TC tumorigenesis by positively regulating GCN5 and PI3K/AKT signaling. These findings provide new research directions and therapeutic options considering PFKF4B as a novel diagnosis marker and therapeutic target.

lncRNA SNHG6 functions as a ceRNA to up-regulate c-Myc expression via sponging let-7c-5p in hepatocellular carcinoma.

Emerging evidence has revealed that dysregulation of lncRNAs correlate with the development and progression of hepatocellular carcinoma (HCC). In the present study, we globally investigated the expression of SNHG6 in 31 cancer type, and we found that SNHG6 was highly expressed in various cancers, especially in HCC. High expression of SNHG6 was associated with progression and poor prognosis in patients with HCC. Gain of function and loss of function assays showed that SNHG6 promoted HCC cell proliferation. Gene Set Enrichment Analysis (GSEA) and correlation analysis suggested that SNHG6 positively correlated with c-Myc and its downstream targets. Ectopic overexpression of SNHG6 markedly increased the expression of c-Myc and its downstream targets, whereas silencing SNHG6 had the opposite effect on the expression of c-Myc and its downstream targets. Mechanistic assays revealed that SNHG6 acted as a competing endogenous RNA (ceRNA) to sponge let-7c-5p and thereby modulating the depression of c-Myc by let-7c-5p. Taken together, SNHG6 promotes HCC cell proliferation via competitively binding let-7c-5p in hepatocellular carcinoma.

Research progress on the autonomous flowering time pathway in Arabidopsis.

The transition from vegetative to reproductive growth phase is a pivotal and complicated process in the life cycle of flowering plants which requires a comprehensive response to multiple environmental aspects and endogenous signals. In Arabidopsis, six regulatory flowering time pathways have been defined by their response to distinct cues, namely photoperiod, vernalization, gibberellin, temperature, autonomous and age pathways, respectively. Among these pathways, the autonomous flowering pathway accelerates flowering independently of day length by inhibiting the central flowering repressor FLC. FCA, FLD, FLK, FPA, FVE, FY and LD have been widely known to play crucial roles in this pathway. Recently, AGL28, CK2, DBP1, DRM1, DRM2, ESD4, HDA5, HDA6, PCFS4, PEP, PP2A-B'γ, PRMT5, PRMT10, PRP39-1, REF6, and SYP22 have also been shown to be involved in the autonomous flowering time pathway. This review mainly focuses on FLC RNA processing, chromatin modification of FLC, post-translational modification of FLC and other molecular mechanisms in the autonomous flowering pathway of Arabidopsis.

Genome-Wide Analysis of the IQM Gene Family in Rice (Oryza sativa L.).

Members of the IQM (IQ-Motif Containing) gene family are involved in plant growth and developmental processes, biotic and abiotic stress response. To systematically analyze the IQM gene family and their expression profiles under diverse biotic and abiotic stresses, we identified 8 IQM genes in the rice genome. In the current study, the whole genome identification and characterization of OsIQMs, including the gene and protein structure, genome localization, phylogenetic relationship, gene expression and yeast two-hybrid were performed. Eight IQM genes were classified into three subfamilies (I-III) according to the phylogenetic analysis. Gene structure and protein motif analyses showed that these IQM genes are relatively conserved within each subfamily of rice. The 8 OsIQM genes are distributed on seven out of the twelve chromosomes, with three IQM gene pairs involved in segmental duplication events. The evolutionary patterns analysis revealed that the IQM genes underwent a large-scale event within the last 20 to 9 million years. In addition, quantitative real-time PCR analysis of eight OsIQMs genes displayed different expression patterns at different developmental stages and in different tissues as well as showed that most IQM genes were responsive to PEG, NaCl, jasmonic acid (JA), abscisic acid (ABA) treatment, suggesting their crucial roles in biotic, and abiotic stress response. Additionally, a yeast two-hybrid assay showed that OsIQMs can interact with OsCaMs, and the IQ motif of OsIQMs is required for OsIQMs to combine with OsCaMs. Our results will be valuable to further characterize the important biological functions of rice IQM genes.

Transcriptome and expression profiling analysis of the hemocytes reveals a large number of immune-related genes in mud crab Scylla paramamosain during Vibrio parahaemolyticus infection.

BACKGROUND: Mud crab Scylla paramamosain is an economically important marine species in China. However, frequent outbreaks of infectious diseases caused by marine bacteria, such as Vibrio parahaemolyticus, result in great economic losses. METHODOLOGY/PRINCIPAL FINDINGS: Comparative de novo transcriptome analysis of S. paramamosain infected with V. parahaemolyticus was carried out to investigate the molecular mechanisms underlying the immune response to pathogenic bacteria by using the Illumina paired-end sequencing platform. A total of 52,934,042 clean reads from the hemocytes of V. parahaemolyticus-infected mud crabs and controls were obtained and assembled into 186,193 contigs. 59,120 unigenes were identified from 81,709 consensus sequences of mud crabs and 48,934 unigenes were matched proteins in the Nr or Swissprot databases. Among these, 10,566 unigenes belong to 3 categories of Gene Ontology, 25,349 to 30 categories of KEGG, and 15,191 to 25 categories of COG database, covering almost all functional categories. By using the Solexa/Illumina's DGE platform, 1213 differentially expressed genes (P<0.05), including 538 significantly up-regulated and 675 down-regulated, were detected in V. parahaemolyticus-infected crabs as compared to that in the controls. Transcript levels of randomly-chosen genes were further measured by quantitative real-time PCR to confirm the expression profiles. Many differentially expressed genes are involved in various immune processes, including stimulation of the Toll pathway, Immune Deficiency (IMD) pathway, Ras-regulated endocytosis, and proPO-activating system. CONCLUSIONS/SIGNIFICANCE: Analysis of the expression profile of crabs under infection provides invaluable new data for biological research in S. paramamosain, such as the identification of novel genes in the hemocytes during V. parahaemolyticus infection. These results will facilitate our comprehensive understanding of the mechanisms involved in the immune response to bacterial infection and will be helpful for diseases prevention in crab aquaculture.