Lecture 5 - Regulation of Gene Expression Flashcards
Alternative promoter use and regulation of the NF-kB pathway are forms of what type of genetic regulation?
Transcriptional regulation
Use of alternative promoters allows for:
different isoforms of a particular protein
What type of regulation involves controlling the access of RNA polymerase to the gene?
Transcriptional control
There is a strong ________ correlation between DNA methylation and chromatin accessibility.
Inverse
What type of regulation involves control at the level of alternative splicing or polyadenylation?
Post-transcriptional control
Alternative splicing and polyadenylation are types of ______.
RNA processing
What type of regulation involves control at the level of mRNA transport and mRNA stability?
Post-transcriptional control
What two classes of elements are involved in transcriptional control?
- cis-acting elements
2. activator or repressor proteins
What element(s) function to bind DNA and/or interact with transcription proteins?
Activator or repressor proteins
DNA sequence elements adjacent to or within the gene are called: _______
cis-acting elements
Imprinted genes are an example of what type of transcriptional regulation?
DNA methylation
Covalent modification of histones (such as acetylation and methylation) may regulate a gene by producing changes in: __________
local chromatin structure
What are two examples of covalent modifications of histones?
Acetylation
Methylation
Binding a regulatory protein to ______ elements of the DNA may either activate or repress transcription.
cis-acting elements
Many promoters lack a TATA box and use _________ instead.
initiator (INR) element - note: this is functionally analogous. The core promoter of individual genes need not contain all elements of a promoter region.
Eukaryotic promoters contain conversed sites that are bound by: _____.
Ubiquitous transcription factors
What is one example of a promoter with a variety of sequence elements recognized by ubiquitous and tissue-specific transcription factors?
Human insulin gene promoter
The _________ gene is often regulated by alternative promoter use, so that alternative promoters can generate tissue-specific isoforms.
Dystrophin gene
What form of post-transcriptional regulation determines whether an antibody molecule is secreted or remains membrane-bound/?
Regulation of the site of RNA cleavage and poly-A addition
What allows for the cleavage of membrane bound OR secreted forms of immunoglobulin?
Alternative polyadenylation
Is a-tropomyosin made in striated muscle different from that made from the same gene in smooth muscle? How does this occur?
It is different because of alternative splicing - the primary transcript can be spliced in different ways to produce distinct mRNAs, which then give rise to different proteins.
Regulation of ferritin heavy chain and transferrin receptor production by iron is what form of post-transcriptional control?
Control of mRNA translation and stability.
Processing of human apolipoprotein B rRMA in the intestine is an example of tissue-specific __________.
RNA editing (a form of post-transcriptional control)
MicroRNAs are very small and regulate gene expression by what type of mechanism?
An antisense mechanism
RNAi is an important form of gene expression regulation that utilizes ___________ RNAs.
antisense
_______ are encoded by noncoding regions of the genome as well as by introns of protein coding genes.
MiRNAs
In RNA interference, the target mRNAs can either be degraded or their translation inhibited based on what?
Their degree of mismatch between the miRNA and mRNA
The degree of mismatch between the miRNA and the mRNA during RNAi can determine whether a target mRNA is ________ or _________
degraded or translation inhibited
A single mRNA can be regulated by __________;
a single miRNA can regulate ________.
A single mRNA can be regulated by multiple miRNAs;
a single miRNA can regulate multiple mRNAs.
MiRNA expression profiles have been shown to be significantly altered in:
a variety of human diseases, including cancers. They can potentially be used for early diagnosis and prognosis of disease.
Iron levels in the body stimulate production of ferritin protein without a corresponding increase in the levels of mRNA. Which of the following best describes this phenomenon?
A. RNA editing
B. Alternative splicing
C. Translational regulation
D. Ubiquitination
C.
a-tropomyosin regulates contraction in muscle cells. The primary transcript can be spliced in different ways to produce distinct mRNAs, which then give rise to variant proteins - for example, in striated vs. smooth muscle cells.
Which of the following best describes this phenomenon?
A. RNA editing B. Alternative splicing C. Translational regulation D. Ubiquitination E. Alternative polyadenylation
B.
In unstimulated B lymphocytes, an intron sequence near the 3’ end is removed to provide an mRNA that codes for membrane-bound antibody molecule. After antigen stimulation, however, the RNA transcript is cleaved upstream from the intron’s 3’ splice site. Some of the intron sequence remains as a coding sequence in the short transcript and the antibody molecule is secreted.
Which of the following best describes this phenomenon?
A. RNA editing B. Alternative splicing C. Translational regulation D. Ubiquitination E. Alternative polyadenylation
E.
In the liver, a codon CAA of the APOB mRNA specifies glutamine but is replaced by U in the intestine to make stop codon UAA.
Which of the following best describes this phenomenon?
A. RNA editing B. Alternative splicing C. Translational regulation D. Ubiquitination E. Alternative polyadenylation
A.
