Chap 17 RQ - Genectics

Which of these are molecular mechanisms that underlie epigenetic control of gene expression? (4)

- Covalent histone modification - Localization of histone variants - Chromatin remodeling - DNA methylation

Which are the three most common ways that the functions of regulatory transcription factors are controlled?

- Covalent modifications - Protein-protein interactions - The binding of a small effector molecule

TFIID binds to the _______ box and helps recruit RNA polymerase II to the core __________

- TATA (box) - (core) promoter

Place the steps in glucocorticoid hormone and receptor action in order, with the first step at the top. (5)

1. The glucocorticoid hormone diffuses through the plasma membrane. 2. The glucocorticoid hormone binds to the glucocorticoid receptors. 3. HSP90 is released from the glucocorticoid receptor. 4. Two glucocorticoid receptors form a homodimer and travel through a nuclear pore into the nucleus. 5. The homodimer binds to a glucose response element and activates transcription of the adjacent gene

What kind of protein is expected to enhance the ability of TFIID to initiate transcription?

Activator protein

Stretches of DNA of 1000-2000 bp in length containing a high number of methylation sites and found near gene promoters are called ______

CpG islands

5-methylcytosine is formed by ______

DNA methyltransferase

Select the most common process regarding methylation

Maintenance methylation

True or false: The methylation state of DNA is inherited during cell division

True

A regulatory transcription factor that enhances the rate of transcription is called a(n) ________

activator

Relative to the promoter for a gene of interest, regulatory elements are located ______

at various distances

A protein that increases the rate of transcription but does not directly bind to the DNA is called a(n) _______

coactivator

For Arabidopsis, flowering in spring due to exposure of colder temperatures in the winter is associated with ______ modification of _____ that occurs in the winter and persists into the spring

covalent; histones

The methylation of a previously unmethylated site is called ______

de novo methylation

Steroid hormones are synthesized by _______ glands and secreted into the bloodstream, ultimately affecting the transcription or expression of genes in target cells.

endocrine

Repressors bind to ________

silencers

A protein that influences the ability of RNA polymerase to transcribe a given gene is a(n) _______ _______

transcription factor

An epigenetic change occurring during development is the marking of histone H3 through a process called ______

trimethylation

During development, covalent modification of Histone H3 by ______ at position 4 is an activating mark but the same change at position 27 is a repressive mark

trimethylation

In general ______ CpG islands correlate with active genes, and ______ CpG islands correlate with suppressed genes.

unmethylated; methylated

An enhancer is a DNA element that is bound by a regulatory transcription factor, which leads to ______

up regulation

In which ways can methylation affect transcription? (2)

- Methyl-CpG binding proteins recruit other proteins that inhibit transcription - The methylation of CpG islands may prevent or enhance the binding of regulatory transcription factors to the promoter region

Which of these are environmental factors that promote epigenetic changes? (3)

- Temperature - Toxins - Diet

Gene regulation can occur during which of the following? (4)

- Transcription - Translation - RNA processing - Posttranslational modification

Plants and animals require a greater level of gene regulation than single-celled eukaryotes because of ______ (4 different reasons)

- developmental stages - multicellularity - more complex cell structure - different tissue types

Repressors inhibit TFIID by ______ (2)

- inhibiting the ability of TFIID to recruit RNA polymerase II to the core promoter - preventing the binding of TFIID to the TATA box

Transcription factors that affect the ability of RNA polymerase to begin the transcription process may work by ______

- regulating the binding of the transcriptional complex to the core promoter - controlling the switch from the initiation to the elongation stage of transcription

DNA sequences in eukaryotes that can be bound by regulatory transcription factors, which then affect the ability of RNA polymerase to transcribe a particular gene are called ______ (3)

- regulatory sequences - regulatory elements - control elements

Which are examples of how gene regulation benefits eukaryotic organisms?

- the ability to respond to changes in nutrient availability - the ability to respond to environmental stresses

In eukaryotes, DNA methyltransferase is an enzyme that attaches a methyl group to the _____ position of the ____ base

5 ; cytosine

As a result of a diet of royal jelly, queen bees develop differences in _____ when compared with worker bees.

DNA methylation

True or false: Regulatory elements must be located within 200 base pairs upstream from the core promoter.

False

General transcription factors are required for the binding of _______ ______ to the core promoter and its progression to the elongation stage

RNA polymerase

During Drosophila development, the protein complex trithorax group (TrxG) causes gene ________ , while polycomb group (PcG) complex causes gene _______

activation; repression

DNA methylation is the _____ attachment of methyl groups to DNA

covalent

Regulatory elements that inhibit transcription are called silencers and their effect on transcription is called ______ regulation.

down

Glucocorticoid response elements are located near ______ genes.

dozens of different

Steroid hormones are synthesized by ________ glands and secreted into the bloodstream, ultimately affecting the transcription or expression of genes in target cells

endocrine

A glucocorticoid response element functions as a(n) ______

enhancer

Activators bind to ______

enhancers

During embryonic development, many genes undergo ______ changes that enable them to be transcribed or cause them to be permanently repressed.

epigenetic

What type of mechanism is responsible for enabling the transcription of muscle-specific genes in an embryonic cell that will eventually give rise to muscle tissue?

epigenetic changes

Methylation of the cytosine in both strands is called ______ methylation, and methylation of only one strand is called _______

full; hemimethylation

Gene regulation means that ______

gene expression can be controlled so that genes can be expressed at high or low levels

Human nerve cells and muscle cells look quite different from each other due to differences in ______

gene regulation

Genes that code for proteins that are required in most cells of a multicellular organism are called ______

housekeeping genes

In genomic _______, specific genes are _______ during oogenesis or spermatogenesis, but not both.

imprinting; methylated

In a multicellular organism, housekeeping genes tend to be expressed ______

in most cell types

A process called _______ methylation seems to be the primary mechanism by which DNA in vertebrate and plant cells is methylated.

maintenance

The methylation of hemimethylated sites is called ______

maintenance methylation

CpG islands near the promoters of tissue-specific genes are often ______

methylated

The covalent attachment of a -CH3 group to DNA is known as DNA ______

methylation

The function of a regulatory transcription factor can be modulated by covalent modifications, such as the attachment of a ______ group

phosphate

If gene regulation acts to prevent translation, which molecule will not be produced?

protein

Following the binding of a hormone, two glucocorticoid ______ form a dimer and travel to the cell's ________

receptors ; nucleus

DNA sequences that are analogous to the operator sites found near bacterial promoters are called ________ elements or _______ elements

regulatory ; control

Regulatory transcription factors that prevent transcription from occurring are called _______

repressors

The function of TFIID is inhibited by proteins called ________, which prevent the binding of TFIID to the _______ box

repressors ; TATA

X-chromosome inactivation occurs in ______cells of ______ mammals

somatic; female

In genomic imprinting, following fertilization, if a gene is methylated only during spermatogenesis, ______

the allele from the father will be methylated in the somatic cells of the offspring, but the allele from the mother will be unmethylated

Genes that are highly regulated and may be expressed only in certain cell types are called ______ - ______ genes

tissue - specific