What are histones and their role in regulating transcription.
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
What are histones and their role in regulating transcription.
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
Solution
Histones are alkaline proteins which are found inside the nucleus of eukaryotic cells that
condense and structure the DNA into units called nucleosomes.They function as spools for the
thread like DNA to wrap around and play a role in gene regulation.
2 types of histones
Core histones (H2A, H2B, H3and H4) and linker his tones ( H1 and H5).
Histone methylation (lysine methylation) can either activate or repress gene expression
depending on both the location of the modified lysine and which his tone is the target. For
example, if this occurs in histone H3 at lysine 4, it is linked to gene activation and if it occurs at
lysine 9 it is a marker for gene silencing.
His tone acetylation removes the negative charge from lysine so it can no longer bind to the
DNA phosphate backbone. This weakens the interaction between histones and DNA, resulting in
a more relaxed DNA structure which is more available for DNA transcription. Histone acetyl
transferase (HAT) complexes are recruited by transcription activator proteins, while the repressor
proteins recruit his tone deacetylase (HDAC) complexes. These add and remove acetylations
respectively..
What are histones and their role in regulating transcription. .pdf
1. What are histones and their role in regulating transcription.
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
What are histones and their role in regulating transcription.
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
What is histone methylation and histone acetylation and how do these effect transcription.
How are genes subdivided?
Solution
Histones are alkaline proteins which are found inside the nucleus of eukaryotic cells that
condense and structure the DNA into units called nucleosomes.They function as spools for the
thread like DNA to wrap around and play a role in gene regulation.
2 types of histones
Core histones (H2A, H2B, H3and H4) and linker his tones ( H1 and H5).
Histone methylation (lysine methylation) can either activate or repress gene expression
depending on both the location of the modified lysine and which his tone is the target. For
example, if this occurs in histone H3 at lysine 4, it is linked to gene activation and if it occurs at
lysine 9 it is a marker for gene silencing.
His tone acetylation removes the negative charge from lysine so it can no longer bind to the
DNA phosphate backbone. This weakens the interaction between histones and DNA, resulting in
2. a more relaxed DNA structure which is more available for DNA transcription. Histone acetyl
transferase (HAT) complexes are recruited by transcription activator proteins, while the repressor
proteins recruit his tone deacetylase (HDAC) complexes. These add and remove acetylations
respectively.
