Transcription template strand

Cellular protein biosynthesis involves the following steps. One strand of double-stranded DNA serves as a template strand for the synthesis of a complementary single-stranded messenger ribonucleic acid (mRNA) in a process called transcription. This mRNA in turn serves as a template to direct the synthesis of the protein in a process called translation. The codons of the mRNA are read sequentially by transfer RNA (tRNA) molecules, which bind specifically to the mRNA via triplets of nucleotides that are complementary to the particular codon, called an anticodon. Protein synthesis occurs on a ribosome, a complex consisting of more than 50 different proteins and several stmctural RNA molecules, which moves along the mRNA and mediates the binding of the tRNA molecules and the formation of the nascent peptide chain. The tRNA molecule carries an activated form of the specific amino acid to the ribosome where it is added to the end of the growing peptide chain. There is at least one tRNA for each amino acid. 

The DNA strand that is complementary to the template strand copied by RNA polymerase during transcription has a nucleotide... 

Unlike what happens in DNA replication, where both strands are copied, only one of the two DNA strands is transcribed into mRNA. The strand that contains the gene is often called the coding strand, or primer strand, and the strand that gets transcribed is called the template strand. Because the template strand and the coding strand are complementary, and because the template strand and the transcribed RNA are also complementary, the RNA )no ecule produced during transcription is a copy of the DNA coding strand. The only difference is that the RNA molecule has a U everywhere the DNA coding strand has a T. 

Transcription (DNA), 1108-1109 coding strand in, 1108 primer strand in, 1108 promoter sites in, 1108 template strand in, 1108 Transfer RNA, 1108... 

Nielsen P. E., Egholm M., Buchardt O. Sequence-specific transcription arrest by peptide nucleic acid bound to the DNA template strand. Gene 1994 149 139-145. 

Figure 35-8. The relationship between the sequences of an RNA transcript and its gene, in which the coding and template strands are shown with their polarities. The RNA transcript with a 5 to 3 polarity is complementary to the template strand with its 3 to 5 polarity. Note that the sequence in the RNA transcript and its polarity is the same as that in the coding strand, except that the U of the transcript replaces theT of the gene.

Figure 37-1. This figure illustrates that genes can be transcribed off both strands of DNA. The arrowheads indicate the direction of transcription (polarity). Note that the template strand is always read in the 3 to 5 direction. The opposite strand is called the coding strand because it is identical (except for T for L) changes) to the mRNA transcript (the primary transcript in eukaryotic cells) that encodes the protein product of the gene.

Figure 37-2. RNA polymerase (RNAP) catalyzes the polymerization of ribonucleotides into an RNA sequence that is complementary to the template strand of the gene. The RNA transcript has the same polarity (5 to 3 ) as the coding strand but contains L) rather than T. E coli RNAP consists of a core complex of two a subunits and two p subunits (P and p ). The holoen-zyme contains the 0 subunit bound to the ajPP core assembly. The co subunit is not shown. The transcription "bubble" is an approximately 20-bp area of melted DNA, and the entire complex covers 30-75 bp, depending on the conformation of RNAP.

The genetic information within the nucleotide sequence of DNA is transcribed in the nucleus into the specific nucleotide sequence of an RNA molecule. The sequence of nucleotides in the RNA transcript is complementary to the nucleotide sequence of the template strand of its gene in accordance with the base-pairing rules. Several different classes of RNA combine to direct the synthesis of proteins. 

RNA polymerase makes a copy of the sense strand of the DNA using the antisense strand as a template (Fig. 5-8). The sequence of the primary transcript is the same as that of the sense strand of the DNA. RNA polymerase needs no primer—only a template. Either of the two DNA strands can serve as the template strand. Which DNA strand is used as the tern-... 

The answer is A. Because all nucleic acids are synthesized in the 5 to 3 direction, mRNA and the coding strand of DNA must each be oriented 5 to 3, i.e., in the direction of transcription. This means that the bottom strand in this example is the coding strand. The top strand is the template strand. 

With the help of sigma factor, RNA polymerase recognizes and binds to the promoter region. The bacterial promoter contains two consensus sequences, called the Pribnow box (or TATA box) and the -35 sequence. The promoter identifies the start site for transcription and orients the enzyme on the template strand. The RNA polymerase separates the two strands of DNA as it reads the base sequence of the template strand. 

RNA polymerase II separates the strands of the DNA over a short region to initiate transcription and read the DNA sequence. The template strand is read in the 3 to 5 direction as the RNA product (the primary transcript) is synthesized in the 5 to 3 direction. Both exons and introns are transcribed. 

Relationship of RNA transcript to DNA RNA is antiparallel and complementary to DNA template strand RNA is identical (except U substitutes for T) to DNA coding strand ... 

Transcription. For expression of a gene—i. e., synthesis of the coded protein—the DNA sequence information has to be converted into a protein sequence. As DNA itself is not involved in protein synthesis, the information is transferred from the nucleus to the site of synthesis in the cytoplasm. To achieve this, the template strand in the relevant part of the gene is transcribed into an RNA (hnRNA). The sequence of this RNA is thus complementary to that of the template strand (3), but— with the exception of the exchange of thy-... 

A. Transcription is the process by which the template strand of DNA is copied into... 

The two complementary DNA strands have different roles in transcription. The strand that serves as template for RNA synthesis is called the template strand. The DNA strand complementary to the template, the nontemplate strand, or coding strand, is identical in base sequence to the RNA transcribed from the gene,... 

FIGURE 26-2 Template and nontemplate (coding) DNA strands. The two complementary strands of DNA are defined by their function in transcription. The RNA transcript is synthesized on the template strand and is identical in sequence (with U in place ofT) to the nontemplate strand, or coding strand. 

Most p-independent terminators have two distinguishing features. The first is a region that produces an RNA transcript with self-complementary sequences, permitting the formation of a hairpin structure (see Fig. 8-2la) centered 15 to 20 nucleotides before the projected end of the RNA strand. The second feature is a highly conserved string of three A residues in the template strand that are transcribed into U residues near the 3 end of the hairpin. When a polymerase arrives at a termination site with this structure, it pauses (Fig. 26-7). Formation of the hairpin structure in the RNA disrupts several A=U base pairs in the RNA-DNA hybrid segment and may disrupt important interactions... 

The p-dependent terminators lack the sequence of repeated A residues in the template strand but usually include a CA-rich sequence called a rut (rho rhilization) element. The p protein associates with the RNA at specific binding sites and migrates in the 5 —>3 direction until it reaches the transcription complex that is paused at a termination site. Here it contributes to release of the RNA transcript. The p protein has an ATP-depend-ent RNA-DNA helicase activity that promotes translocation of the protein along the RNA, and ATP is hydrolyzed by p protein during the termination process. The detailed mechanism by which the protein promotes the release of the RNA transcript is not known. 

Diverse Functions of TFIIH In eukaryotes, the repair of damaged DNA (see Table 25-5) is more efficient within genes that are actively being transcribed than for other damaged DNA, and the template strand is repaired somewhat more efficiently than the nontemplate strand. These remarkable observations are explained by the alternative roles of the TFIIH subunits. Not only does TFIIH participate in the formation of the closed complex during assembly of a transcription complex (as described above), but some of its subunits are also essential components of the separate nucleotide-excision repair complex (see Fig. 25-24). 

Transcription is catalyzed by DNA-dependent RNA polymerases, which use ribonucleoside 5 -triphosphates to synthesize RNA complementary to the template strand of duplex DNA. Transcription occurs in several phases binding of RNA polymerase to a DNA site called a promoter, initiation of transcript synthesis, elongation, and termination. 

Antisense RNA. Another mechanism of control of either transcription or of plasmid replication involves small molecules of RNA that are transcribed from the opposite strand than the template strand used for mRNA synthesis.1 13 165-166b These antisense RNA molecules have at least some part of their sequence complementary to that of the mRNA and to the corresponding sequence in DNA. A well-studied example is control of the copy number of the colicin El and other plasmids of E. co/i.167-169 Two transcripts, RNAI and RNAII, are initiated upstream from the origin of replication (Fig. 28-8). RNA II is a 555-nucleotide primer of replication. It is synthesized as a longer transcript that is cut by RNase H at ori. This... 

The RNA genomes of single-stranded RNA bacterial viruses, such as Q/3, MS2, R17, and f2, are themselves mRNAs. Bacteriophage Q/3 codes for a polypeptide that combines with three host proteins to form an RNA-depen-dent RNA polymerase (replicase). The three host proteins are ribosomal protein SI and two elongation factors for protein synthesis EF-Tu and EF-Ts (see table 28.5). The Q/3 replicase functions exclusively with the Q/3 RNA plus strand template. It first makes a complementary RNA transcript (minus strand) and ultimately uses the minus strand as... 

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