title: The identification and characteristics of immune-related microRNAs in haemocytes of oyster Crassostrea gigas.
abstract: BACKGROUND
  MicroRNAs (miRNAs) represent a class of small ncRNAs that repress gene expression on the post-transcriptional level by the degradation or translation inhibition of target mRNA.
  
  
  METHODS
  Three small RNA libraries from oyster haemocytes were sequenced on the Illumina platform to investigate the latent immunomodulation of miRNAs after bacteria challenge and heat stress. Totally, 10,498,663, 8,588,606 and 9,679,663 high-quality reads were obtained in the control, bacteria and bacteria+heat library, respectively, from which 199 oyster miRNAs including 71 known and 128 novel ones were identified. Among these miRNAs, 6 known and 23 novel ones were predicted to possess more than one precursor-coding region, and cgi-miR-10a, cgi-miR-184b, cgi-miR-100, cgi-miR-1984 and cgi-miR-67a were observed to be the most abundant miRNAs in the control library. The expression levels of 22 miRNAs in the bacteria library were significantly higher than those in the control library, while there were another 33 miRNAs whose expression levels were significantly lower than that in the control library. Meanwhile, the expression levels of 65 miRNAs in the bacteria+heat library changed significantly compared to those in the bacteria library. The target genes of these differentially expressed miRNAs were annotated, and they fell in immune and stress-related GO terms including antioxidant, cell killing, death, immune system process, and response to stimulus. Furthermore, there were 42 differentially expressed miRNAs detected in both control/bacteria and bacteria/bacteria+heat comparisons, among which 9 miRNAs displayed the identical pattern in the two comparisons, and the expression alterations of 8 miRNAs were confirmed using quantitative RT-PCR.
  
  
  CONCLUSIONS
  These results indicated collectively that immune challenge could induce the expression of immune-related miRNAs, which might modulate the immune response such as redox reaction, phagocytosis and apoptosis, and the expression of some immune-related miRNAs could be also regulated by heat stress to improve the environmental adaption of oyster.
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors: Zhi
authors: Z
authors: Zhou
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors: Lingling
authors: L
authors: Wang
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors: Linsheng
authors: L
authors: Song
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors: Rui
authors: R
authors: Liu
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors: Huan
authors: H
authors: Zhang
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China ; University of Chinese Academy of Sciences, Beijing, China.
authors: Mengmeng
authors: M
authors: Huang
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China ; University of Chinese Academy of Sciences, Beijing, China.
authors: Hao
authors: H
authors: Chen
mesh_terms: D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D049896:Crassostrea / Q000166:cytology / Q000235:genetics* / Q000276:immunology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D063990:Gene Ontology; D018869:Heat-Shock Response / Q000235:genetics; D006434:Hemocytes / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D017423:Sequence Analysis, RNA
chemical_list: D035683:MicroRNAs