Indentification And Analysis Of MicroRNAs During The Early Regeneration Of The Optic Nerve In Zebrafish

MicroRNAs(miRNAs)are 21-23nucleotide(nt)single-stranded noncod-ing RNAs. By binding to complementary sequences located at the 3’-untranslated region(3’-UTR) of target mRNAs, miRNAs inhibit translation an/or lead to the degradation of target mRNAs. miRNAs play a very important role in the organism, they can be involved in a variety of physiological processes, such as cell differentiation, apoptosis, neuron development, lipid metabolosm, hormone secretion and so on. The optic nerve ia a visual way from optic disc to optic chiasma and mainly composed of the axons of retinal ganglion cell(RGCs), as a special differentiation of central nervous stystem. Because of its convenient operation characteristics, so as to become the typical representative of the central nervous system. Zebrafish as a important patterns animalsr of research neural development and regeneration after injury, it can be recycled back to the target tissue, formed the retino-tectal projection that the same as the original after optic nerve injury and restored normal physiological function. However, human optic nerve’s regeneration ability is limitd after injury, in recent years, research has shown that the expression of miRNAs have changed dramatically during the regeneration of nerve, so investigating the related regulatory function of miRNAs during the regeneration of optic nerve in zebrafish, to provide important basis of molecular biology research for understanding the molecular regulation mechanism during the regeneration of central nerve.In order to fully understand the related regulatory fuction of miRNAs during the early regeneration of the optic nerve in zebrafish, this study used the HiSeq 2500 high-throughput sequencing platform, built 2 Small RNA(sRNA libraries:the normal zebrafish (A) and the early regeneration of the optic nerve after optic nerve injury 1 day(B), analyzed the deep sequencing data of sRNA from the two libraries using bioinformatics approaches, identified the related miRNAs during the early regeneration of the optic nerve, analyzed and forecast the of these expression of these miRNAs and the potential function.There are major results based on investigation above, as follows:1.A total of 17,614,833 and 15,607,126 high quality reads were obtained from the two libraries, after removing the reads of low quality and masking adaptor sequences, a total of 11,714,910 and 11,637,612 clean reads of 17 to 46 nucleotides in length were obtained from the two librariesone respectively. In these clean reads, the vast majority were 21 nt in length, consistent with the common size of miRNAs. In the two libraries, matching rate were 99.71% and 99.54% respectively with the known zebrafish genome.2.Combining the data from two libraries identified a total of 200 unique mature miRNAs.192 miRNAs overlapped between the two libraries,1 miRNAs were detected only in the normal zebrafish retinal tissue and 7 miRNAs were detected only in the retinal tissue of optic nerve injury 1 day. Of the 192 coexpression miRNAs,18 miRNAs were up-regulated, and 17 miRNAs were down-regulated in the the retinal tissue of optic nerve injury 1 day.3.Through Mireap software to predict, found 26 new miRNAs.14 miRNAs overlapped between the two libraries,8 miRNAs were detected only in the normal zebrafish retinal tissue and 4 miRNAs were detected only in the retinal tissue of optic nerve injury 1 day.4.The 1580,1416 predicted target genes of the 15 most abundant and differential expression miRNAs from the two libraries were analyzed in bioinformatics. The KEGG pathway analysis results showed that significant enriched pathways targeted by miRNA in the two aspect including neural development, cell biological process. The result shows that the potential role of the most abundance and differential expression miRNAs during the early regeneration of the optic nerve in zebrafish, further validated our sequencing results.