Abstract-The coxsackievirus and adenovirus receptor (CAR), which mediates infection by the viruses most commonly associated with myocarditis, is a transmembrane component of specialized intercellular junctions, including the myocardial intercalated disc; it is known to mediate cell-cell recognition, but its natural function is poorly understood. We used conditional gene targeting to investigate the possible functions of CAR during embryonic development, generating mice with both germline and tissue-specific defects in CAR expression. Homozygous germline deletion of CAR exon 2 or cardiomyocyte-specific gene deletion at embryonic day 10 (E10) mediated by Cre recombinase expressed under the control of the cardiac troponin T promoter resulted in death by E12.5; embryos showed marked cardiac abnormalities by E10.5, with hyperplasia of the left ventricular myocardium, distention of the cardinal veins, and abnormalities of sinuatrial valves. Within the hyperplastic left ventricle, increased numbers of proliferating cells were evident; persistent expression of N-myc in the hyperplastic myocardium and attenuated expression of the trabecular markers atrial natriuretic factor and bone morphogenic protein 10 indicated that proliferating cardiomyocytes had failed to differentiate and form normal trabeculae. In electron micrographs, individual CAR-deficient cardiomyocytes within the left ventricle appeared normal, but intercellular junctions were ill-formed or absent, consistent with the known function of CAR as a junctional molecule; myofibrils were also poorly organized. When cardiomyocyte-specific deletion occurred somewhat later (by E11, mediated by Cre under control of the ␣-myosin heavy chain promoter), animals survived to adulthood and did not have evident cardiac abnormalities. These results indicate that during a specific temporal window, CAR expression on cardiomyocytes is essential for normal cardiac development. In addition, the results suggest that CAR-mediated intercellular contacts may regulate proliferation and differentiation of cardiomyocytes within the embryonic left ventricular wall. Key Words: adhesion molecules Ⅲ cardiac development Ⅲ cardiomyopathy Ⅲ coxsackievirus receptor Ⅲ hyperplasia Ⅲ intercellular junctions Ⅲ mouse heart development T he coxsackievirus and adenovirus receptor (CAR) is a 46-kDa cell surface protein that mediates attachment and infection by group B coxsackieviruses and many adenoviruses. 1,2 CAR has been conserved during vertebrate evolution, with homologs identified in mammals, birds, frogs, and fish, 3 but its natural functions are not well understood. Recent work demonstrates that CAR mediates homotypic 4,5 and heterotypic 6 intercellular interactions and that it is a component of specialized intercellular junctions, including the epithelial tight junction 4 and the cardiac intercalated disc. 7 Although distinct CAR-mediated signals have not been defined, CAR expression in tumor cell lines leads to changes in the activity of cell cycle regulators that are associated with slower g...
BackgroundNitrogen (N) is a key macronutrient essential for plant growth, and its availability has a strong influence on crop development. The application of synthetic N fertilizers on crops has increased substantially in recent decades; however, the applied N is not fully utilized due to the low N use efficiency of crops. To overcome this limitation, it is important to understand the genome-wide responses and functions of key genes and potential regulatory factors in N metabolism.ResultsHere, we characterized changes in the rice (Oryza sativa) transcriptome, including genes, newly identified putative long non-coding RNAs (lncRNAs), and microRNAs (miRNAs) and their target mRNAs in response to N starvation using four different transcriptome approaches. Analysis of rice genes involved in N metabolism and/or transport using strand-specific RNA-Seq identified 2588 novel putative lncRNA encoding loci. Analysis of previously published RNA-Seq datasets revealed a group of N starvation-responsive lncRNAs showing differential expression under other abiotic stress conditions. Poly A-primed sequencing (2P-Seq) revealed alternatively polyadenylated isoforms of N starvation-responsive lncRNAs and provided precise 3′ end information on the transcript models of these lncRNAs. Analysis of small RNA-Seq data identified N starvation-responsive miRNAs and down-regulation of miR169 family members, causing de-repression of NF-YA, as confirmed by strand-specific RNA-Seq and qRT-PCR. Moreover, we profiled the N starvation-responsive down-regulation of root-specific miRNA, osa-miR444a.4-3p, and Degradome sequencing confirmed MADS25 as a novel target gene.ConclusionsIn this study, we used a combination of multiple RNA-Seq analyses to extensively profile the expression of genes, newly identified lncRNAs, and microRNAs in N-starved rice roots and shoots. Data generated in this study provide an in-depth understanding of the regulatory pathways modulated by N starvation-responsive miRNAs. The results of comprehensive, large-scale data analysis provide valuable information on multiple aspects of the rice transcriptome, which may be useful in understanding the responses of rice plants to changes in the N supply status of soil.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4897-1) contains supplementary material, which is available to authorized users.
BackgroundLong non-coding RNAs (lncRNAs) are a class of RNAs that do not encode proteins. Recently, lncRNAs have gained special attention for their roles in various biological process and diseases.ResultsIn an attempt to identify long intergenic non-coding RNAs (lincRNAs) and their possible involvement in honey bee development and diseases, we analyzed RNA-seq datasets generated from Asian honey bee (Apis cerana) and western honey bee (Apis mellifera). We identified 2470 lincRNAs with an average length of 1011 bp from A. cerana and 1514 lincRNAs with an average length of 790 bp in A. mellifera. Comparative analysis revealed that 5 % of the total lincRNAs derived from both species are unique in each species. Our comparative digital gene expression analysis revealed a high degree of tissue-specific expression among the seven major tissues of honey bee, different from mRNA expression patterns. A total of 863 (57 %) and 464 (18 %) lincRNAs showed tissue-dependent expression in A. mellifera and A. cerana, respectively, most preferentially in ovary and fat body tissues. Importantly, we identified 11 lincRNAs that are specifically regulated upon viral infection in honey bees, and 10 of them appear to play roles during infection with various viruses.ConclusionsThis study provides the first comprehensive set of lincRNAs for honey bees and opens the door to discover lincRNAs associated with biological and hormone signaling pathways as well as various diseases of honey bee.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1868-7) contains supplementary material, which is available to authorized users.
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