Control of Gene Expression

The classic experiment that demonstrated that a differentiated cell contains a complete genome involved transplanting the nucleus of a skin cell from an adult frog into an enucleated frog egg. What was the result of this experiment?

According to the overview of gene expression control, what is the most common point of control for most genes, ensuring that the cell does not synthesize superfluous intermediates?

Transcription regulators recognize specific DNA sequences without needing to open the double helix. Where do they primarily make their contacts?

Dimerization is a common strategy for transcription regulators to increase their affinity and specificity for DNA. What is a key advantage of forming heterodimers compared to homodimers?

The E. coli Lac operon is a classic example of combinatorial control. Under which set of conditions is the operon fully activated, leading to high expression of the LacZ gene?

What is the primary role of the Mediator protein complex in eukaryotic transcription?

What is the term for a DNA sequence that prevents a cis-regulatory sequence from inappropriately activating an adjacent gene, often by helping to form chromatin loops?

The regulation of the Drosophila Even-skipped (Eve) gene results in seven stripes of expression. How is this precise pattern achieved?

What is the term for the phenomenon where a heritable alteration in a cell's phenotype does not result from changes in the nucleotide sequence of its DNA?

In vertebrate cells, DNA methylation is a key mechanism for epigenetic inheritance. What enzyme is responsible for faithfully propagating the methylation pattern to daughter DNA strands after replication?

What is the phenomenon called where the expression of a small minority of mammalian genes depends on whether they were inherited from the mother or the father?

What long noncoding RNA is responsible for initiating X-chromosome inactivation in female mammals by coating the chromosome from which it is transcribed?

What is the primary mechanism of action for microRNAs (miRNAs) in humans?

How do riboswitches, often found in bacteria, control gene expression?

What is the outcome of A-to-I RNA editing when it occurs within a protein-coding region of an mRNA?

What is the primary function of RNA interference (RNAi) pathways that involve small interfering RNAs (siRNAs)?

How does the bacterial CRISPR system provide adaptive immunity against viruses?

Which of the following is a proposed unifying feature and function of many long noncoding RNAs (lncRNAs)?

What is the role of the 3' untranslated region (UTR) in the localization of many mRNAs within the cytoplasm?

The stability of eukaryotic mRNAs is often controlled by the length of their poly-A tail. What is the general process that initiates the decay of most mRNAs?

How does phosphorylation of the eukaryotic translation initiation factor eIF2 globally regulate protein synthesis?

What is the function of upstream open reading frames (uORFs) in regulating the translation of some eukaryotic mRNAs, such as that for the yeast protein Gcn4?

What type of control allows a single gene, such as the Drosophila Dscam gene, to produce up to 38,000 different protein isoforms?

In the case of regulated polyadenylation of the antibody gene in B lymphocytes, what change leads to the switch from producing a membrane-bound antibody to a secreted one?

What is the primary role of piwi-interacting RNAs (piRNAs) in the germ line of animals?

Approximately what percentage of the protein-coding genes in most organisms is devoted to producing transcription regulators?

What is the typical length of a cis-regulatory sequence recognized by a transcription regulator?

The control region of the Drosophila Eve gene, which is approximately 20,000 nucleotide pairs long, is responsible for specifying its expression in how many precisely positioned stripes?

A typical human cell expresses what percentage of its protein-coding and noncoding RNA genes at any one time?

How much can the rate of transcription vary for a vertebrate gene between different tissues, representing a much higher degree of repression than in bacteria?

What is the typical outcome for the transcription of the mouse Igf2 gene, which is subject to genomic imprinting?

Out of the approximately 900 protein-coding genes on the human X chromosome, what is the approximate percentage that escapes X-inactivation and remains actively expressed?

What is the primary function of a positive feedback loop in the context of cell memory and differentiation?

What type of gene regulatory circuit, which involves two transcription regulators where one regulates the other and both regulate a target gene, can act as a filter to respond to prolonged signals but ignore brief ones?

What term describes the phenomenon where the combined effect of several transcription activators working together is much greater than the sum of their individual effects?

How can the artificial expression of just three specific transcription regulators (Oct4, Sox2, and Klf4) in a mouse fibroblast alter its fate?

Which of the following is a mechanism by which eukaryotic transcription activators increase transcription initiation?

Which of the following is a mechanism of gene repression in eukaryotes that involves the creation of a heritable, self-propagating silent chromatin state?

What are CG islands, and with which types of genes are they typically associated in the human genome?

What type of post-transcriptional control involves a change in the site of 3' end cleavage and polyadenylation?

In the iron-dependent regulation of ferritin and transferrin receptor mRNAs, how does the protein aconitase function?

What are cytoplasmic P-bodies primarily involved in?

How is RNA-directed transcriptional silencing (RITS) initiated?

Long noncoding RNAs (lncRNAs) are defined as RNA molecules that do not code for protein and are longer than how many nucleotides?

Which statement accurately describes the binding properties of the tryptophan repressor in E. coli?

What is the key difference in how eukaryotic and bacterial RNA polymerases recognize promoters?

What is a 'pioneer factor' in the context of eukaryotic gene regulation?

In bacteria, it is common for a single mRNA molecule to encode several different proteins. What is the term for such an mRNA?

How do cells use 'leaky scanning' during translation initiation to produce different protein isoforms?

What are internal ribosome entry sites (IRESs)?