title: Identification of putative miRNAs from the deep-branching unicellular flagellates.
abstract: MicroRNAs (miRNAs) are a class of extensively studied RNAi-associated small RNAs that play a critical role in eukaryotic gene regulation. However, knowledge on the miRNA and its regulation in unicellular eukaryotes is very limited. In order to obtain a better understanding on the origin of miRNA regulation system, we used deep-sequencing technology to investigate the miRNA expression pattern in four deep-branching unicellular flagellates: Giardia lamblia, Trichomonas vaginalis, Tritrichomonas foetus, and Pentatrichomonas hominis. In addition to the known miRNAs that have been described in G. lamblia and T. vaginalis, we identified 14 ancient animal miRNA families and 13 plant-specific families. Bioinformatics analysis also identified four novel miRNA candidates with reliable precursor structures derived from mature tRNAs. Our results indicated that miRNAs are likely to be a general feature for gene regulation throughout unicellular and multicellular eukaryotes and some of them may derive from unconventional ncRNAs such as snoRNA and tRNA.
authors: Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan.
authors: Po-Jung
authors: PJ
authors: Huang
authors: Wei-Chen
authors: WC
authors: Lin
authors: Shih-Chieh
authors: SC
authors: Chen
authors: Yong-Han
authors: YH
authors: Lin
authors: Chin-Hung
authors: CH
authors: Sun
authors: Ping-Chiang
authors: PC
authors: Lyu
authors: Petrus
authors: P
authors: Tang
mesh_terms: D002874:Chromosome Mapping; D020869:Gene Expression Profiling; D016829:Giardia lamblia / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D016834:Trichomonadida / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D016053:RNA, Protozoan