Gene regulation & cell phenotypes & epigenetic Flashcards
What are the 2 main domains of transcription factors? and how they work
Transregulatory domain - Interacts with other components of the transcriptional complex
DNA binding domain - binds to specific DNA sequences
Explanation from chatgpt
In simple terms, the activation domain is like the conductor in an orchestra, orchestrating the performance (transcription) of the gene by bringing in the musicians (helper proteins and enzymes) and making sure they play their parts to produce the gene’s RNA. This orchestration is crucial for the precise and controlled regulation of gene expression in the cell.
what are hox genes
Hox genes, also known as homeobox genes, are a family of highly conserved genes that play a fundamental role in the development of organisms, particularly in specifying the body plan and segment identity of animals during embryonic development. These genes are found in a wide range of animals, from fruit flies to humans, and they have been critical in the evolution of multicellular organisms.
explain the importance of nucleocytoplasmic interactions and describe J.B Gordon’s experiment
the cytoplasm influences the nucleus extensively by modulating gene expression.
This is shown in the experiment carried out by J.B Gurdon
Skin cells are taken from a adult frog
UV is used to destroy the nucleus of an unfertilised egg and its replaced with the nucleus of the skin cell.
a healthy embryo is formed which forms a healthy tadpole.
How are cells de
Define epigenetics
Reconfiguring the DNA activity without altering the primary structure
What is the benefit of epigenetic over changing the primary structure of DNA
Epigenetic modifications normally DNA methylation of histone modification which are reversible enzymatic processes
How is the X chromosome inactivated
XIST RNA which is produced form the x inactivation centre, recruits histone and DNA modification enzymes which will kickoff a set of reaction that compress the DNA of the X chromosome
this meaning its inaccessible to transcriptional regulatory complexes
What is genetic imprinting
Genomic imprinting is an epigenetic phenomenon in genetics that results in the differential expression of genes depending on whether they are inherited from the mother or the father. In other words, certain genes are “imprinted” with epigenetic marks (chemical modifications to the DNA) that affect their activity, and this imprinting is specific to the parent from whom the gene was inherited. This phenomenon leads to differences in gene expression between the two alleles (gene copies) inherited from the mother and father. e.g. Igf2r
QUESTION ASKED BY EMAIL
What is a CpG island
A Cpg island is a stretch of DNA between 200-2000 base pairs, which has a high concentration of Cytosine and Guanine dinucleotides.
These regions are often located near gene promoters and play a role in gene regulation. CpG islands can be methylated, which can influence gene expression.
What causes an open chromatin configuration?
Acetylated histones and unmethylated DNA
where does the methyl group attach to the DNA in DNA methylation?
A methyl group (CH3) attached to the 5th carbon on a cytosine
What are DNMTs and their functions and types of DNMTs
DNA methytranserases.
DNMT1 - Maintains existing DNA methylation patterns after DNA replication, and ensures newly synthesised DNA is methylated at the same points as the paternal strand.
DNMT3a/b - De novo DNMTs - involved in the establishment of new DNA methylation patterns, adding methyl groups to previously unmethylated DNA.
DNMT3L - is a cofactor to assist DNMT3A and DNMT3B in their methylation activity.
How are histone modifications carried out?
Methylation and acetylation of specific amino acids of the histone.
How is a histone modified for gene expression
Methylation at Lysine 4 and acetylation at lysine 9
How is a histone modified for gene silencing / heterochromatin formation
Methylation at lysine 9 and 27
