3.2 - Transcription: Gene Structure Flashcards
What is the difference between the regulatory region and the transcribed region?
A transcribed region is the part of the gene’s sequence that is used to direct the synthesis of an RNA molecule. Within the transcribed region is the region of the RNA that actually encodes the polypeptide, through the process of translation - this is known as the coding region. A regulatory region is the region of a gene where RNA Polymerase and other accessory transcription modulator Proteins bind and interact to control RNA synthesis.
What and where is the promoter region?
A promoter is a sequence of DNA to which proteins bind that initiate transcription of a single RNA from the DNA downstream of it. This RNA may encode a protein, or can have a function in and of itself, such as tRNA, mRNA, or rRNA. Promoters are located near the transcription start sites of genes, upstream on the DNA.
In bacteria, the promoter contains two short sequence elements approximately 10 and 35 nucleotides upstream from the transcription start site.
Eukaryotic promoters are diverse and can be difficult to characterize. Recent studies show that they are divided in more than 10 classes. Eukaryotic RNA-polymerase-II-dependent promoters can contain a TATA box (consensus sequence TATAAA), which is recognized by the general transcription factor TATA-binding protein (TBP); and a B recognition element (BRE), which is recognized by the general transcription factor TFIIB. The TATA element and BRE typically are located close to the transcriptional start site.
Source: Gershenzon NI, Ioshikhes IP (April 2005). “Synergy of human Pol II core promoter elements revealed by statistical sequence analysis”. Bioinformatics.
How to determine the upstream and downstream regions of the genome?
Upstream is toward the 5’ end of the RNA molecule and downstream is toward the 3’ end. When considering double-stranded DNA, upstream is toward the 5’ end of the coding strand for the gene in question and downstream is toward the 3’ end.
What is the difference between the template strand and the non-template (coding) strand in DNA?
Tne strand serves as a template for transcription at any given time is called the template/noncoding strand. The other nontemplate strand is called coding strand because its sequence will be the same as that of the new RNA molecule.
What is the difference between transcription in bacteria and eukaryotes?
In bacteria, transcription and translation can occur simultaneously in the cytoplasm of the cell, whereas in eukaryotes transcription occurs in the nucleus and translation occurs in the cytoplasm.
