Biological Sciences
Prokaryotic Gene Expression
Prokaryotic gene expression refers to the process by which genes in prokaryotic cells are transcribed and translated to produce proteins. This process involves the binding of RNA polymerase to the promoter region of the gene, followed by transcription and translation of the mRNA into a functional protein. Prokaryotic gene expression is tightly regulated to ensure that the correct proteins are produced at the right time.
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10 Key excerpts on "Prokaryotic Gene Expression"
eBook - PDF- Mary Ann Clark, Jung Choi, Matthew Douglas(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
As eukaryotic cells evolved, the complexity of the control of gene expression increased. For example, with the evolution of eukaryotic cells came compartmentalization of important cellular components and cellular processes. A nuclear region that contains the DNA was formed. Transcription and translation were physically separated into two different cellular compartments. It therefore became possible to control gene expression by regulating transcription in the nucleus, and also by controlling the RNA levels and protein translation present outside the nucleus. Most gene regulation is done to conserve cell resources. However, other regulatory processes may be defensive. Cellular processes such as developed to protect the cell from viral or parasitic infections. If the cell could quickly shut off gene expression for a short period of time, it would be able to survive an infection when other organisms could not. Therefore, the organism evolved a new process that helped it survive, and it was able to pass this new development to offspring. 16.2 | Prokaryotic Gene Regulation By the end of this section, you will be able to do the following: • Describe the steps involved in prokaryotic gene regulation • Explain the roles of activators, inducers, and repressors in gene regulation The DNA of prokaryotes is organized into a circular chromosome, supercoiled within the nucleoid region of the cell cytoplasm. Proteins that are needed for a specific function, or that are involved in the same biochemical pathway, are encoded together in blocks called operons. For example, all of the genes needed to use lactose as an energy source are coded next to each other in the lactose (or lac) operon, and transcribed into a single mRNA. In prokaryotic cells, there are three types of regulatory molecules that can affect the expression of operons: repressors, activators, and inducers. Repressors and activators are proteins produced in the cell.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
_______________________________ WORLD TECHNOLOGIES ______________________________ Chapter 4 Gene Expression Genes are expressed by being transcribed into RNA, and this transcript may then be translated into protein. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA) genes or transfer RNA (tRNA) genes, the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (including multi-cellular organisms), prokaryotes (bacteria and archaea) and viruses - to generate the macromolecular machinery for life. Several steps in the gene expression process may be modu-lated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype. The genetic code stored in DNA is interpreted by gene expression, and the properties of the expression give rise to the organism's phenotype. _______________________________ WORLD TECHNOLOGIES ______________________________ Mechanism Transcription The process of transcription is carried out by RNA polymerase (RNAP), which uses DNA (black) as a template and produces RNA (blue). The gene itself is typically a long stretch of DNA which carries genetic information encoded by genetic code.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- College Publishing House(Publisher)
______________________________ WORLD TECHNOLOGIES ______________________________ Chapter 4 Gene Expression Genes are expressed by being transcribed into RNA, and this transcript may then be translated into protein. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA) genes or transfer RNA (tRNA) genes, the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (including multi-cellular organisms), prokaryotes (bacteria and archaea) and viruses - to generate the macro-molecular machinery for life. Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype. The genetic code stored in DNA is interpreted by gene expression, and the properties of the expression give rise to the organism's phenotype. ______________________________ WORLD TECHNOLOGIES ______________________________ Mechanism Transcription The process of transcription is carried out by RNA polymerase (RNAP), which uses DNA (black) as a template and produces RNA (blue). The gene itself is typically a long stretch of DNA which carries genetic information encoded by genetic code.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter- 1 Gene Expression Genes are expressed by being transcribed into RNA, and this transcript may then be translated into protein. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA) genes or transfer RNA (tRNA) genes, the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea) and viruses - to generate the macromolecular machinery for life. Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism. In genetics, gene expression is the most fundamental level at which genotype gives rise to the phenotype. The genetic code stored in DNA in form of nucleotide sequence is ________________________ WORLD TECHNOLOGIES ________________________ interpreted by gene expression, and the properties of the expression products give rise to the organism's phenotype. Mechanism Transcription The process of transcription is carried out by RNA polymerase (RNAP), uses DNA (black) as a template and produces RNA (blue). The gene itself is typically a long stretch of DNA which carries genetic information encoded by genetic code.
eBook - ePub- Chang-Hui Shen(Author)
- 2019(Publication Date)
- Academic Press(Publisher)
Chapter 3Gene Expression: Transcription of the Genetic Code
Abstract
The central dogma of molecular biology is that DNA makes RNA, and RNA makes proteins. This process is called gene expression, and the genetic information is used within a cell to produce the proteins needed for the cell to function. The process of making RNA from DNA is transcription, a process of RNA biosynthesis. It is the first step in gene expression, and it is a vital control point in the expression of genes and production of proteins. In this process, one of the strands of the double-stranded DNA molecule (a template strand) is transcribed into a complementary sequence of RNA. The RNA sequence differs from DNA in three respects: (1) the DNA base thymine (T) is replaced by the RNA base uracil (U); (2) the sugar ring of RNA has a hydroxyl group in the 2′-position, whereas the sugar ring of DNA has a hydrogen group in the 2′-position; and (3) DNA exists as double helix, whereas RNA is single stranded. In this chapter, we discuss the mechanism of transcription in both prokaryotes and eukaryotes. Different types of RNA are also discussed in this chapter.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Research World(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter- 1 Gene Expression Genes are expressed by being transcribed into RNA, and this transcript may then be translated into protein. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA) genes or transfer RNA (tRNA) genes, the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea) and viruses - to generate the macromolecular machinery for life. Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism. In genetics, gene expression is the most fundamental level at which genotype gives rise to the phenotype. The genetic code stored in DNA in form of nucleotide sequence is interpreted by gene expression, and the properties of the expression products give rise to the organism's phenotype. ____________________ WORLD TECHNOLOGIES ____________________ Mechanism Transcription The process of transcription is carried out by RNA polymerase (RNAP), uses DNA (black) as a template and produces RNA (blue). The gene itself is typically a long stretch of DNA which carries genetic information encoded by genetic code.
eBook - ePubBiochemistry
An Integrative Approach with Expanded Topics
- John T. Tansey(Author)
- 2022(Publication Date)
- Wiley(Publisher)
Chapter OutlineThis chapter examines the similarities in different DNA sequences that regulate genes and how DNA-binding motifs found in proteins interact with DNA in both specific and nonspecific ways. Next, it considers how prokaryotes control gene expression both globally and on a gene-by-gene basis, using sigma factors, operons, and riboswitches. Finally, it explores how eukaryotes organize and consolidate DNA into chromosomes and modify gene expression to adapt to their environment. We also discuss biochemical aspects of several human diseases that arise as a result of aberrations in gene expression and the ways they are currently treated or may be treated in the future.17.1 DNA–Protein Interactions17.2 Regulation of Gene Expression in Prokaryotes17.3 Regulation of Gene Expression in EukaryotesCommon ThemesEvolution’s outcomes are conserved. • Organisms face environmental or developmental challenges and must adapt and respond in order to prosper and pass on their genes.• Like protein and nucleic acid structures, the control mechanisms themselves are often conserved. All the common mechanisms of gene regulation (operons, ligand-responsive transcription factors, riboswitches, attenuators, antiterminators, and miRNAs) are found in multiple species and often throughout biology.Structure determines function. • Several different protein structural domains are involved in DNA–protein interactions and, consequently, in DNA-binding proteins used for gene regulation. These domains are structurally conserved.• Like proteins, nucleic acids (specifically RNAs) can form complex but organized tertiary structures.•
No longer available |Learn more- (Author)
- 2014(Publication Date)
- College Publishing House(Publisher)
______________________________ WORLD TECHNOLOGIES______ ________________________ Chapter 4 Gene Expression Genes are expressed by being transcribed into RNA, and this transcript may then be translated into protein. Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA (rRNA) genes or transfer RNA (tRNA) genes, the product is a functional RNA. The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea) and viruses - to generate the macromolecular machinery for life. Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and amount of gene expression can have a profound effect on the functions (actions) of the gene in a cell or in a multicellular organism. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype. The genetic code stored in DNA is interpreted by gene expression, and the properties of the expression give rise to the organism's phenotype. ______________________________ WORLD TECHNOLOGIES______ ________________________ Mechanism Transcription The process of transcription is carried out by RNA polymerase (RNAP), which uses DNA (black) as a template and produces RNA (blue). The gene itself is typically a long stretch of DNA which carries genetic information encoded by genetic code.
eBook - PDF- Donald Voet, Charlotte W. Pratt, Judith G. Voet(Authors)
- 2014(Publication Date)
- Wiley(Publisher)
This is perhaps because prokaryotic mRNAs have lifetimes of only a few minutes, so transla- tional control is less necessary. In this section, we examine a few well- documented examples of gene regulation in prokaryotes. In the following section, we will consider how eukaryotic cells regulate gene expression. A The lac Operon Is Controlled by a Repressor Bacteria adapt to their environments by producing enzymes that metabolize certain nutrients only when those substances are available. For example, E. coli cells grown in the absence of lactose are initially unable to metabolize the disaccharide. To do so they require two proteins: -galactosidase, which catalyzes the hydrolysis of lactose to its component monosaccharides, 1023 C H E C K P O I N T • What is the relationship between genome size and gene number in different organisms? • What are some factors that allow humans to get by with only slightly more genes than invertebrates? • What is the purpose of cataloging SNPs and doing genome-wide association studies? • What are the origins and functions of gene clusters? • Summarize the relationship between genome size, repetitive DNA, transcribed DNA, and protein-coding exons in the human genome. • What is the source of the repetitive DNA in the human genome? See Guided Exploration 30 The regulation of gene expression by the lac repressor system. OH HO H 2 O CH 2 OH H OH H H OH H H O H OH H H OH H H O O Lactose OH HO CH 2 OH H OH H H OH H H O CH 2 OH CH 2 OH H OH H H OH H H O + Galactose OH HO Glucose β -galactosidase Chapter 28 Gene Expression in Prokaryotes and Eukaryotes and galactoside permease (also known as lactose permease; Section 10-3D), which transports lactose into the cell. Cells grown in the absence of lactose contain only a few molecules of the proteins.
eBook - PDF- Bert O'Malley, Lutz Birnbaumer, Bert W. O'Malley(Authors)
- 2012(Publication Date)
- Academic Press(Publisher)
9 Gene Expression in the Eukaryotic Cell R. STEWART G I L M O U R I. Introduction 331 II. Evidence for Differential Gene Transcription 332 III. Possible Mechanisms for Selective Gene Expression 337 A. RNA Polymerase Directed Specificity 337 B. Template Directed Specificity 338 IV. The Role of Nonhistone Proteins in Gene Regulation 342 A. Distribution and Specificity Patterns of Nonhistone Proteins . . . 342 B. Biological Relevance of Nonhistone Proteins 345 V. Problems and Perspectives 349 A. Fidelity of in Vitro Transcription 349 B. Chromatin Reconstitution 351 References 352 I. I N T R O D U C T I O N It is generally accepted that the process of cell differentiation in higher organisms results in the formation of individual cell types whose functional characteristics depend on a selective expression of the genome information. While it is often assumed that transcriptional control is the major mode of gene regulation, the control of mRNA populations through posttranscrip-tional processing could contribute significantly. Obviously both of these as well as various other modes of regulation may coexist. However, since this discussion will concentrate on transcriptional regulation, it is pertinent to consider the evidence which stresses its overall primary importance. 331 332 R. Stewart Gilmour II. E V I D E N C E F O R D I F F E R E N T I A L G E N E T R A N S C R I P T I O N One of the strongest arguments for differential gene activity has come from the study of puffing in the polytene chromosomes of larval Diptera. It has been firmly established that puffs are chromosome sites undergoing active transcription, and detailed analysis of puffing patterns has revealed the presence of tissue-specific puffs as well as characteristic changes with development (see reviews by Ashburner, 1972; Panitz, 1972).
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