Basic Principles of Transcription and Translation - Computer ...

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Organization of a Typical Eukaryotic Gene Associated with most eukaryotic genes are control elements, segments of noncoding DNA that help regulate transcription by binding certain proteins Control elements and the proteins they bind are critical to the precise regulation of gene expression in different cell types Enhancer (distal control elements) DNA Upstream Proximal control elements Primary RNA Transcript (pre-mRNA) mRNA Promoter 5′ Intron RNA 5′ Cap Exon Intron Exon Exon Intron Exon Intron Exon 5’ UTR untranslated region Coding segment Start codon Poly-A signal sequence Termination region Intron Exon Transcription RNA processing Cap and tail added introns excised and exons spliced together Downstream Cleaved 3′ end of primary transcript Poly-A signal 3′ Stop codon 3′ UTR Poly-A tail A eukaryotic gene and its transcript. Each eukaryotic gene has a promoter a DNA sequence where RNA polymerase binds and starts transcription proceeding downstream. A number of control elements (gold) are involved in regulating the initiation of transcription; these are DNA sequences located near (proximal to) or far from (distal to) the promoter. Distal control elements can be grouped together as enhancers one of which is shown for this gene. A polyadenylation (poly-A) signal sequence in the last exon of the gene is transcribed into an RNA sequence that signals where the transcript is cleaved and the poly A tail added. Transcription may continue for hundreds of nucleotides beyond the poly A signal before terminating. RNA processing of the primary transcript into a functional mRNA involves three steps: addition of the 5’ cap addition of the poly A tail and splicing. In the cell the 5’ cap is added soon after transcription is initiated splicing and poly A tail addition may also occur while transcription is till under way.
The Roles of Transcription Factors To initiate transcription, eukaryotic RNA polymerase requires the assistance of proteins called transcription factors General transcription factors are essential for the transcription of all protein-coding genes In eukaryotes, high levels of transcription of particular genes depend on control elements interacting with specific transcription factors Enhancers and Specific Transcription Factors Proximal control elements are located close to the promoter Distal control elements, groups of which are called enhancers, may be far away from a gene or even located in an intron An activator is a protein that binds to an enhancer and stimulates transcription of a gene Bound activators cause mediator proteins to interact with proteins at the promoter
Page 1 and 2: The Flow of Genetic Information Th
Page 3 and 4: TRANSCRIPTION DNA mRNA (a) Bacteria
Page 5 and 6: The Genetic Code How are the instr
Page 7 and 8: Cracking the Code All 64 codons we
Page 9 and 10: Molecular Components of Transcripti
Page 11 and 12: RNA Polymerase Binding and Initiati
Page 13 and 14: Eukaryotic cells modify RNA after t
Page 15 and 16: 5′ Exon Intron Exon Intron Pre-mR
Page 17 and 18: The Functional and Evolutionary Imp
Page 19 and 20: Polypeptide Trp Phe Ribosome Amino
Page 21 and 22: Amino acid P P P ATP Adenosine Amin
Page 23 and 24: Building a Polypeptide The three s
Page 25 and 26: The elongation cycle of translation
Page 27 and 28: Growing polypeptides Completed poly
Page 29 and 30: Polypeptide synthesis always begins
Page 31 and 32: Type of RNA Small nucleolar RNA (sn
Page 33 and 34: RNA polymerase RNA polymerase Polyr
Page 35 and 36: Individual bacteria respond to envi
Page 37 and 38: Eukaryotic gene expression can be r
Page 39 and 40: CYTOPLASM mRNA in cytoplasm Degrada
Page 41 and 42: Histone tails DNA double helix Amin
Page 43: Epigenetic Inheritance Although th
Page 47 and 48: Mechanisms of Post-Transcriptional
Page 49 and 50: Initiation of Translation The init
Page 51 and 52: Noncoding RNAs play multiple roles
Page 53: Chromatin Remodeling and Silencing

Basic Principles of Transcription and Translation - Computer ...

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