Gene Regulation Flashcards
In vertebrates, what DNA base is most commonly methylated to repress gene expression?
Cytosine residues.
What are CpG (CG) sites?
They are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide.
What are the three ways the MeCP2 protein can repress gene expression once bound to methylated DNA?
Once bound, it can condense the chromatin structure, form a complex with histone deacetylases, or block transcription factors directly.
Other than DNA methylation, what other modification can regulate gene expression and how?
Histone modification, which results in the alteration of chromatin structure.
What is a Barr body?
A Barr body is the inactive X chromosome in a female somatic cell.
How does X-inactivation prove the clonal origin of cancerous tumours?
All the tumour cells would have same X-chromosome inactivated, implying that have derived from a single cell.
What changes in DNA methylation occurs during mammalian development?
1) Originally, the zygote is highly methylated, then during early development, the genome undergoes global demethylation.
