Glossary of Terms Note: Words in Bold in a Definition Indicate Terms Also Defined in This Glossary
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Resistance to HIV (Exercise)
1 Evolution in fast motion – Resistance to HIV (Exercise) Resistance to HIV In the early 1990s, a number of studies revealed that some people – although they had repeatedly contact with HIV – did not become carriers of HIV or, in the case of a confirmed HIV-infection, showed a delayed onset of the disease (AIDS) (a delay of several years was reported). First attempts to explain these phenomena were observed a few years later, when scientists identified important co-receptor molecules on the surface of the host cells, which are essential for HIV to infect the host cell. Scientists assumed that resistant persons may carry an aberrant version of the co-receptor molecule, which makes it impossible for the virus to enter the host cell. Such a co-receptor is the chemokine co-receptor CCR5, which is normally involved in the host’s immune answer (Dean & O’Brien, 1998). In order to test their hypothesis, the scientists sequenced the genes which code for the co- receptor CCR5. They investigated more than 700 samples from HIV-infected patients and compared them with the CCR5-sequences from more than 700 healthy persons. The results of the DNA-sequencing revealed mutations in the CCR5-gene in HIV-infected persons with a delayed onset of AIDS, as well as in some samples of healthy persons (but not in HIV- patients with typical onset of AIDS) (Samson et al., 1996). Exercises 1. In material 1, you can find two CCR5-gene-sequences selected from the data set of the scientists. Compare the sequences and a. find out where the mutation is (identify the position and label it in both! sequences). -
News & Views Research
NEWS & VIEWS RESEARCH may exhibit some tissue specificity in humans. Upstream intron Downstream intron a Sibley et al. found that genes with long introns sequence sequence tend to be expressed in the human nervous Precursor RNA system, and they identified recursively spliced 3' Splice 5' Splice RNAs expressed in the human brain6. Duff site site First step et al. detected some selectivity for recursive splicing in the brain in a screen of 20 human tissues (including fetal brain and adult cerebel- Second step lum), but this may partly reflect the difficulty of detecting recursively spliced RNAs in tis- Mature mRNA sues that express such RNAs at low levels. It will be important to determine whether this b RS exon specificity, if real, results from the tendency of recursively spliced genes to be expressed in the brain, or whether cells in the nervous system have factors that promote recursive Competing 5' splice sites First step splicing. Many genes that have long introns, including those that undergo recursive splicing, are linked to neurological diseases and to Second step 9–11 Second step autism . Whether these conditions are sometimes triggered by errors in the multi- step recursive RNA-splicing process will be an exciting avenue for future studies. ■ NMD Heidi Cook-Andersen and Miles F. Wilkinson are in the Department of Reproductive Medicine, University of Figure 1 | Mechanisms of recursive splicing. a, In recursive splicing, long intron sequences of precursor California, San Diego, La Jolla, California, RNA are removed in a stepwise process mediated by juxtaposed internal 3ʹ and 5ʹ splice sites. In the first step, 92093, USA. -
Intronic Mir-26B Controls Neuronal Differentiation by Repressing Its Host Transcript, Ctdsp2
Downloaded from genesdev.cshlp.org on September 30, 2021 - Published by Cold Spring Harbor Laboratory Press RESEARCH COMMUNICATION CTDSPL. As part of the REST complex, these enzymes Intronic miR-26b controls dephosphorylate the C-terminal domain (CTD) of RNA neuronal differentiation polymerase II (PolII) and thereby inhibit the expression of genes that have an RE1 signature sequence (Yeo et al. by repressing its host 2005; Visvanathan et al. 2007). During neural fate com- ctdsp2 mitment and terminal differentiation, the REST/CTDSP transcript, pathway is gradually inactivated to allow the expression Holger Dill,1 Bastian Linder,1 Alexander Fehr,2 of RE1-containing genes (Ballas et al. 2005; Yeo et al. 3 2005; Visvanathan et al. 2007). Neuronal gene activation and Utz Fischer in mice and humans is known to depend on the action of Department of Biochemistry, Theodor Boveri-Institute, miR-124, which prevents expression of CTDSPs (Lim University of Wu¨ rzburg, D-97074 Wu¨ rzburg, Germany et al. 2005; Conaco et al. 2006; Visvanathan et al. 2007). However, as shown in mice, the neuron-specific miR-124 Differentiation of neural stem cells (NSCs) to neurons is itself repressed by the REST/CTDSP pathway, since all of its loci contain an RE1 (Conaco et al. 2006). As mRNAs requires the activation of genes controlled by the re- often are under the control of a collection of microRNAs pressor element 1 (RE1) silencing transcription factor (miRNAs) (Krek et al. 2005), we therefore hypothesized (REST)/neuron-restrictive silencer factor (NRSF) protein that additional miRNAs might be involved in the regu- complex. Important components of REST/NRSF are phos- lation of CTDSP activity. -
(Bsc Zoology and Microbiology) Concept of Introns and Exons
Unit-5 Molecular Biology (BSc Zoology and Microbiology) Concept of introns and exons Most of the portion of a gene in higher eukaryotes consists of noncoding DNA that interrupts the relatively short segments of coding DNA. The coding sequences are called exons. The noncoding sequences are called introns. Intron: An intron is a portion of a gene that does not code for amino acids An intron is any nucleotide sequence within a gene which is represented in the primary transcript of the gene, but not present in the final processed form. In other words, Introns are noncoding regions of an RNA transcript which are eliminated by splicing before translation. Sequences that are joined together in the final mature RNA after RNA splicing are exons. Introns are very large chunks of RNA within a messenger RNA molecule that interfere with the code of the exons. And these introns get removed from the RNA molecule to leave a string of exons attached to each other so that the appropriate amino acids can be encoded for. Introns are rare in genes of prokaryotes. #Look carefully at the diagram above, we have already discussed about the modification and processing of eukaryotic RNA. In which 5’ guanine cap and 3’poly A tail is added. So at that time, noncoding regions i.e. introns are removed. We hv done ths already. Ok Exon: The coding sequences are called Exon. An exon is the portion of a gene that codes for amino acids. In the cells of plants and animals, most gene sequences are broken up by one or more DNA sequences called introns. -
Lecture 1 1. to Understand the Flow of Biochemical Information from DNA to RNA to Proteins and Ultimately to Biochemical And
Lecture 1 1. To understand the flow of biochemical information from DNA to RNA to proteins and ultimately to biochemical and cellular function and dysfunction (disease) Central Dogma: DNARNAProteinPhenotype NucleotidegeneDNAchromosomegenome - In reality it is much more complex DNA sequence RNA sequence Protein sequence Protein structure Protein function RNA structure RNA function Know: - Structure of DNA/RNA and proteins - Intermolecular interactions: o Hydrogen bonds o Disulfur bonds o Ion bonds o Polar bonds - Main aspects of the central dogma o Translation (at the ribosome) o Transcription o Genetic code DNA structure: - Sugar-phosphate backbone - 4 bases o A/G = purines o T/C = pyrimidines o A-T and G-C - 5’-3’ antiparallel (always read 5’3’) o Addition occurs at the 3’ end o 5’ position to commence reading depends on promotor o Reading frame depends on promotor - Coding and template strand: o Depends on the position of the promotor RNA structure: - U replaces T - Self-complementarity = annealing of strand to itself - tRNA/mRNA/pre-RNA - Spliced (exons remain) to form mature RNA Therefore 6: - 3 from the codon from the top 5’ end, 3 from the codon from the bottom 5’ end. Protein Structure: Chemical Properties Depends on N or C-terminus, peptide bonds and side chains - Non-polar aliphatic - Polar but uncharged - Aromatic - Positively charged - Negatively charged pKa = pH at which the protein has a charge of zero. Alpha-helices: side chains point sideways Beta-helices: - Parallel and anti-parallel to produce alternate the direction the side chains point - In reality, there is a combination of parallel and anti-parallel side chains - Different bonds between NH and CO groups in each direction of side chain Sample Question 1. -
Current Perspectives in Intronic Micro Rnas (Mirnas)
Journal of Biomedical Science (2006) 13:5–15 5 DOI 10.1007/s11373-005-9036-8 Current perspectives in intronic micro RNAs (miRNAs) Shao-Yao Ying & Shi-Lung Lin Department of Cell & Neurobiology, Keck School of Medicine, BMT-403, University of Southern California, 1333 San Pablo Street, Los Angeles, CA, 90033, USA Received 27 May 2005; accepted 14 September 2005 Ó 2005 National Science Council, Taipei Key words: fine-tuning of gene function, functional/structural genomics, gene expression, genetic regula- tion, intronic microRNA, miRNA biogenesis, miRNA, post-translational modification, regulatory gene Summary MicroRNAs (miRNAs), small single-stranded regulatory RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. Numerous miRNAs have been reported to induce RNA interference (RNAi), a post-transcriptional gene silencing mechanism. Intronic miRNAs, derived from introns by RNA splicing and Dicer processing, can interfere with intracellular mRNAs to silence that gene expression. The intronic miRNAs differ uniquely from previously described intergenic miRNAs in the requirement of type II RNA polymerases (Pol-II) and spliceosomal components for its biogenesis. Several kinds of intronic miRNAs have been identified in Caenorhabditis elegans, mouse and human cells; however, neither their function nor application has been reported. To this day, the computer searching program for miRNA seldom include the intronic portion of protein-coding RNAs. The functional significance of artificially generated intronic miRNAs has been successfully ascertained in several biological systems such as zebrafishes, chicken embryos and adult mice, indicating the evolutionary pres- ervation of this gene regulation system in vivo. -
IGA 8/E Chapter 8
8 RNA: Transcription and Processing WORKING WITH THE FIGURES 1. In Figure 8-3, why are the arrows for genes 1 and 2 pointing in opposite directions? Answer: The arrows for genes 1 and 2 indicate the direction of transcription, which is always 5 to 3. The two genes are transcribed from opposite DNA strands, which are antiparallel, so the genes must be transcribed in opposite directions to maintain the 5 to 3 direction of transcription. 2. In Figure 8-5, draw the “one gene” at much higher resolution with the following components: DNA, RNA polymerase(s), RNA(s). Answer: At the higher resolution, the feathery structures become RNA transcripts, with the longer transcripts occurring nearer the termination of the gene. The RNA in this drawing has been straightened out to illustrate the progressively longer transcripts. 3. In Figure 8-6, describe where the gene promoter is located. Chapter Eight 271 Answer: The promoter is located to the left (upstream) of the 3 end of the template strand. From this sequence it cannot be determined how far the promoter would be from the 5 end of the mRNA. 4. In Figure 8-9b, write a sequence that could form the hairpin loop structure. Answer: Any sequence that contains inverted complementary regions separated by a noncomplementary one would form a hairpin. One sequence would be: ACGCAAGCUUACCGAUUAUUGUAAGCUUGAAG The two bold-faced sequences would pair and form a hairpin. The intervening non-bold sequence would be the loop. 5. How do you know that the events in Figure 8-13 are occurring in the nucleus? Answer: The figure shows a double-stranded DNA molecule from which RNA is being transcribed. -
RNA Splice Sites Classification Using Convolutional Neural Network Models
RNA Splice Sites Classification Using Convolutional Neural Network Models Thanyathorn Thanapattheerakul Worrawat Engchuan Daniele Merico School of Information Technology, The Centre for Applied Genomics, Molecular Diagnostics, King Mongkut’s University of Genetics and Genome Biology, The Deep Genomics, Technology Thonburi, Hospital for Sick Children, Toronto, Ontario, Canada Bangkok, Thailand Toronto, Ontario, Canada [email protected] [email protected] [email protected] Narumol Doungpan Kiyota Hashimoto Jonathan H. Chan Faculty of Engineering, Faculty of Technology and School of Information Technology, King Mongkut’s University of Environment, King Mongkut’s University of Technology Thonburi, Prince of Songkla University, Technology Thonburi, Bangkok, Thailand Phuket, Thailand Bangkok, Thailand [email protected] [email protected] [email protected] Abstract—RNA splicing refers to the elimination of non- completely make it loss of function. The alternative splicing coding region on transcribed pre-messenger ribonucleic acid can produce different functional proteins, which could lead (RNA). Identifying splicing site is an essential step which can to causing abnormal states in human [3]. be used to gain novel insights of alternative splicing as well as Many studies have proposed models to recognize the splicing defects, potentially cause malfunction of protein splice sites to reveal which splice sites contain a mutation resulting from mutations at splice site. In this work, we that may cause a splicing error. One common method to propose a data preprocessing step applying to RNA sequences recognize binding sites in motif sequences is called Position- and the models leveraging Convolutional Neural Network (CNN). The preprocessing step includes reducing sequence Weight-Matrix (PWM). -
The CTD Role in Cotranscriptional RNA Processing and Surveillance
CORE Metadata, citation and similar papers at core.ac.uk Provided by Elsevier - Publisher Connector FEBS Letters 582 (2008) 1971–1976 Minireview The CTD role in cotranscriptional RNA processing and surveillance Se´rgio F. de Almeida, Maria Carmo-Fonseca* Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal Received 4 April 2008; revised 13 April 2008; accepted 14 April 2008 Available online 22 April 2008 Edited by Ulrike Kutay proteins specific to each snRNP. The selection of specific splice Abstract In higher eukaryotes, the production of mature mes- senger RNA that exits the nucleus to be translated into protein sites (ss) on a particular pre-mRNA substrate relies on an intri- requires precise and extensive processing of the nascent tran- cate interplay involving the cooperative binding of trans-acting script. The processing steps include 50-end capping, splicing, splicing proteins to cis-acting sequence elements in the pre- and 30-end formation. Pre-mRNA processing is coupled to tran- mRNA. In mammals, an intron is defined by four short and scription by mechanisms that are not well understood but involve poorly conserved consensus sequences: the exon–intron junc- the carboxyl-terminal domain (CTD) of the largest subunit of tions (50ss and 30ss); the branch point sequence; and the poly- RNA polymerase II. This review focuses on recent findings that pyrimidine tract (Table 1). These sequences are recognized by provide novel insight into the role of the CTD in promoting RNA base pairing with the spliceosomal snRNAs (Fig. 1). In addi- processing and surveillance. tion, both exons and introns contain weak binding sites for a Ó 2008 Federation of European Biochemical Societies. -
Synthesis of Orthogonal Transcription- Translation Networks
Synthesis of orthogonal transcription- translation networks Wenlin An and Jason W. Chin1 Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom Edited by Susan Gottesman, National Institutes of Health, Bethesda, MD, and approved April 2, 2009 (received for review January 11, 2009) Orthogonal, parallel and independent, systems are one key foun- O-ribosomes for the translation of an O-mRNA arises from the dation for synthetic biology. The synthesis of orthogonal systems altered 16S rRNA in the O-ribosome that recognizes an altered that are uncoupled from evolutionary constraints, and selectively Shine-Dalgarno sequence in the leader sequence of the O-mRNA abstracted from cellular regulation, is an emerging approach to in the initiation phase of translation (12). In previous work O- making biology more amenable to engineering. Here, we combine ribosomes have been evolved that decode genetic information in orthogonal transcription by T7 RNA polymerase and translation by orthogonal mRNAs in new ways. In combination with orthogonal orthogonal ribosomes (O-ribosomes), creating an orthogonal gene aminoacyl-tRNA synthetases and tRNAs that recognize unnatural expression pathway in Escherichia coli. We design and implement amino acids the evolved O-ribosomes have allowed us to begin to compact, orthogonal gene expression networks. In particular we undo the ‘‘frozen accident’’ of the natural genetic code and direct focus on creating transcription–translation feed-forward loops the efficient incorporation of unnatural amino acids into proteins (FFLs). The transcription–translation FFLs reported cannot be cre- encoded on O-mRNAs (13, 14). O-ribosomes have also been used ated by using the cells’ gene expression machinery and introduce to create new translational Boolean logic functions that would not information-processing delays on the order of hours into gene be possible to create by using the essential cellular ribosome (15) expression. -
LESSON 4 Using Bioinformatics to Analyze Protein Sequences
LESSON 4 Using Bioinformatics to 4 Analyze Protein Sequences Introduction In this lesson, students perform a paper exercise designed to reinforce the student understanding of the complementary nature of DNA and how that complementarity leads to six potential protein reading frames in any given DNA sequence. They also gain familiarity with the circular format codon table. Students then use the bioinformatics tool ORF Finder to identify the reading frames in their DNA sequence from Lesson Two and Lesson Three, and to select Class Time the proper open reading frame to use in a multiple sequence alignment with 2 class periods (approximately 50 their protein sequences. In Lesson Four, students also learn how biological minutes each). anthropologists might use bioinformatics tools in their career. Prior Knowledge Needed • DNA contains the genetic information Learning Objectives that encodes traits. • DNA is double stranded and At the end of this lesson, students will know that: anti-parallel. • Each DNA molecule is composed of two complementary strands, which are • The beginning of a DNA strand is arranged anti-parallel to one another. called the 5’ (“five prime”) region and • There are three potential reading frames on each strand of DNA, and a total the end of a DNA strand is called the of six potential reading frames for protein translation in any given region of 3’ (“three prime”) region. the DNA molecule (three on each strand). • Proteins are produced through the processes of transcription and At the end of this lesson, students will be able to: translation. • Amino acids are encoded by • Identify the best open reading frame among the six possible reading frames nucleotide triplets called codons. -
Base Paring Rules for Transcription
Base Paring Rules For Transcription Jerry window-shop his Jon traversings unduly or shortly after Giff vacillated and nerves turbulently, Silvanintoxicated labialised and camouflaged. unofficially if attentionalSynchronistic Martin Moore compel twigging, or puzzling. his clapboard curses leasing grindingly. Since the template strand will contain base pairs that bond precisely with the. Dna Base Pair Worksheet Teachers Pay Teachers. Most images show 17 base pairs The coding strand turns gray page then disappears leaving the template strand see strands above Anti-codons in the template. DNA Base Pairing Worksheet 1 CGTAAGCGCTAATTA 2. One strand whereas the DNA duplex the template strand is transcribed into a segment of mRNA shown according to the prior base-pairing rules used in DNA. As surgery the damage of DNA replication base-pairing rules apply However. Base pairs refer them the sets of hydrogen-linked nucleobases that window up nucleic acids DNA and RNA. Students begin by replicating a DNA strand and transcribing the DNA strand into RNA Then they create base pairing rules and search the. Topic 27 DNA Replication Transcription and Translation. Transcribe the DNA strand until the complementary base pairs. Therefore translation of the messenger RNA transcribed from this mutant. DNA RNA Transcription and Translation Protein Synthesis. The base-pairing rules summarize which The template strand despite the DNA contains the gene and is being transcribed pairs of nucleotides are complementary. Transcription Translation & Protein Synthesis Gene. The cell's DNA contains the instructions for carrying out the work of border cell. Rules of Base Pairing A with T the purine adenine A always pairs with the pyrimidine thymine T C with G the pyrimidine cytosine C always.