Lecture 10 Flashcards
the complex of chromosomal DNA and the proteins that associate with the DNA across regions of the chromosome.
Chromatin
don’t really have chromatin although there are some proteins binding the DNA
Bacteria
What type of chromatin conformation allows transcription to take place
Open conformation
What kind of Heterochromatin? Always there, used for genome stability
Constitutive
What kind of Heterochromatin? Signals cause it to be assembled or disassembled, control gene expression
Faculatative
Bacterial restriction enzymes cleave ___ DNA regardless of whether it is packaged in euchromatin or heterochromatin
eukaryotic
Is an enzyme that cleaves DNA into many tiny pieces
DNase 1
eukaryotic DNase I cleaves DNA more readily when it is in….
Euchromatin
Cannot stop the DNase 1 from cleaving DNA into little pieces
Euchromatin
Stops the DNase 1 from cleaning the dna of the gene
Heterochromatin
What kind of molecules run further in a Southern Blot
Small
Why does DNA get stuck in the nylon membrane?
Because of its Positive charge
the b-globin locus expresses hemoglobin subunit only in blood cells is an example of what kind of chromatin
Facultative Heterochromatin
A type of anemia (less oxygen delivered to the body) caused by a deletion in on copy of the b-globin locus
Beta-Thalassemia
Sout hern blots show that
the Hispanic Thalassemic deletion leads to DNase I insensitivity at what gene?
beta globin gene
The hispanic deletion Removes the…
LCR
The heterochromatin at the Beta-globin locus is an example of
epigenetic gene regulation
is heritable gene expression or gene silencing that can be passed from cell to cell or from generation to generation and is reversible, but does not involve a change in the DNA sequence.
Epigenetic gene inheritance
Epigenetic gene inheritance contains what chromatin structures
Repressive
forms over repetitive sequences and spreads beyond the repetitive sequences
Constitutive Heterochromatin (repressive)
Clusters of repetitive sequences form continuous ___ domains
heterochromatin
Many copies of a repetitive sequence reinforce each other in the formation of ___. Such “strong” ___ spreads variable distances into ___.
heterochromatin, heterochromatin, Euchromatin
When Heterochromatin spreads, it does what to the reporter gene?
When it contracts, what happens to the reporter gene?
Silences, expressed
Heterochromatin and Euchromatin compete for the ____.
What wins more if overexpressed?
Genome, euchromatin
DNA methylation occurs in hetero or euchromatin
Heterochromatin
In dna methylation, only __ gets methylated, followed by __
Cytosines, guanine
he Agouti gene more highly expressed unmethylated when the ERV is in…
Euchromatin
What is healthier: agouti or yellow fur
Agouti
What supplement in diet of mice is a methyl donor for DNA Methylation?
Folate
Folate promotes what color of mice
Agouti
Alcohol effects what: agouti and yellow fur
Higher proportion of agouti color
What fraction of amino acids in histone in tails form nucleosome
1/4
When dna is in euchromatin, ___ of all 4 histone tails get acetylated
Lysine
The amino acids in each histone are numbered starting at the tip of the
N terminal tail
Thr ee alternate tri-methylation sites on Histone ___ represent three alternate repressive chromatin (heterochromatin) structures.
H3
Features of closed/repressive chromatin (Heterochromatin)
3 methyls on lysine 9, lysine 27, lysine 36
causes the nucleosome to be bound by a protein called ‘Heterochromatin Protein 1’ (HP1)
Lysine 9 of H3
causes the nucleosome to be bound by a complex of Polycomb (heterochromatin) proteins called ‘PRC1’
Lysine 27 on H3
proteins that bind nucleosomes with this histone modification have not (yet) been identified
Lysine 36 H3
