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Evolutionary exploitation of miRNA by phylogeny tree construction Presentation: Shaojun Tang* Shizhao Zhou** *Genetics Institute, College of Medicine, University of Florida **Computer information and science engineering, University of Florida Mentor: Tamer Kahveci
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Outline Part I: What and why miRNA ? Part II: Gene regulation governed by transcription binding and miRNA targeting. Part III: Phylogeny tree construction of miRNA from different organism. Part IV: Multiply sequence alignment analysis to identify evolutionary conserved miRNAs.
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Part I: What and why miRNA. What is miRNA. Ribonucleic acid(RNA) molecules of about 21–23 nucleotides long, which regulation gene expression.
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Function of miRNA 1: Mature miRNA molecules are partially complementary to one or more message RNA (mRNA) molecules, which down-regulate gene expression 2: miRNA regulation of gene expression are associated with many disease and even cancer.
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Current research of miRNA 1: more than 700 miRNAs are identified in humans 2: miRNA regulation of gene transcription is important, but poorly understood and addressed. 3: miRNA can be a powerful tool in helping solve many disease or cancer in human.
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Part II Gene regulation governed by transcription factor and miRNA Transcription factor (sequence-specific DNA binding factor) Specific factors such as protein, that binds to particular DNA sequence and thereby controls the gene transcription from DNA to RNA. Transcription factor Gene Binding site
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Methods 1: Database of transcription factor, human pathway genes, miRNA targets. 2: Calculate occurrence of transcription factor(the gene controlling factors) and downstream miRNA target sites. Pathway A TF-kTF-m TAR-iTF-k TAR-i TAR-j Gene-1 Gene-n PathwayTFTAR A k = 2 m=1 i=2 J=1 B ---------
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Results 871 pathways each associated with a group(20) of high- frequency transcription factor and miRNA targets. Important for study pathway gene regulation and disease.
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Part III: Phylogeny tree construction Data for analysis All available miRNA sequences from Human, mice, drosophila and virus. Algorithm Dynamic program to generate scoring-matrix, follow by implementing UPGMA method to cluster miRNA sequences. Methods Using two approaches for self-verification and more powerful evidence.
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Method implementation-1 Forward-construction (low => high) Individual miRNA Cluster of miRNA Overlap miRNAs
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Finding pairwise clusters of miRNA Cluster of miRNAs individual miRNAs Closely related miRNA cluster 2 1 1 4 3 5 2 ---- 1 5
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Method implementation-2 Backward-construction miRNA clusters from UPGMA Individual miRNA
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Data Organisms KSHV Kaposi's sarcoma-associated herpesvirus EBV Epstein-Barr virus Dm Drosophila melanogaster Mm Mus_musculus Hs Homo_Sapiens Groups of phylogeny tress 1: KSHV => Dm => Hs 2: Ebv => Dm => Mm
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Results of a Single group 1): Forward construction 3 tables from Edit(0, 1, 1) : (0, 1 3) : Percentage 2 ): Backward construction 3 tables from Edit(0, 1, 1) : (0, 1 3) : Percentage
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Conclusion 1: The association of transcription factor binding site and miRNA targets given the pathway can provide useful information for research related to pathways. 2: The UPGMA construction of phylogeny tree may provide useful information for clustering evolutionary conserved genes in any given organism,. 3: while our two methods of miRNA pairwise construction among organism may shield light on future research in miRNA evolution, regulation and function.
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Thank you
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