From genes to cells to cell behaviours Flashcards
What is emergent behaviour?
The organisation of cells at one level, interacting with each other in an environment to form more complex behaviours as a collective
What is the function of a cell reflected in?
The shape of the cell
How do chromosomes, which are identical in each cell direct cell differences?
Differential gene activity causing the restriction of potency
How can gene expression in different cells be altered?
Autonomously/cell intrinsically
Non-autonomously/cell extrinsically
What is autonomous/cell intrinsic control?
The cell controls itself
What is non-autonomous/cell extrinsic control?
Factors from other cells control the cell in question
How does development occur?
It is progressive, cells gradually become committed to their fates by restricting their potency
What is a ‘ restriction in potency’ and when does it occur?
The cell is capable of differentiating into fewer cell types - occurs when the cell becomes committed to its fate
What is ‘cell fate’?
The final cell type that a developing cell will become, as it goes through development and restricts its potency
What does differential gene expression produced?
Change in gene transcription
How is mammalian differentiation achieved?
Systematic, sequential changes in gene expression, brought about through interactions between the NUCLEUS and CHANGING CYTOPLASMIC ENVIRONMENT
What determines if the cell is going to change transcriptional profile?
Signalling between the nucleus and the cytoplasmic environment of the cell
How can gene expression be regulated?
- Chromatin modification
- Transcription
- Transport to cytoplasm
- Translation
- Degradation of mRNA
- Protein processing
- Degradation of protein
- Transport to cellular destination
DIFFERENTIAL REGULATION AT THE LEVEL OF GENE ENHANCERS AND GENE PROMOTERS
What are enhancers?
Part of the DNA sequence which sit upstream or downstream of the coding sequence and can increase or decrease transcription of a gene
What binds to enhancers in DNA? Causing what to happen?
Activator proteins to help to activate transcription by opening up the genome and allow transcription machinery to access it
Repressor proteins (silencers) bind to repress transcription
Transcription factors bind
What are promoters?
Part of the DNA sequence which sit upstream of the coding sequence, near the transcription start site, indicate where transcription of DNA by RNApol occurs
RNApol binds here
How do transcription factors usually act?
In a complex with many other proteins (cotranscription factors/ coregulatory elements)
What acts together to control the expression of a single gene?
What do we focus on in BMS249?
Many enhancer elements and numerous transcription factors
Focus on the individual TF which is the dominant TF which determines if a gene is expressed
What determines if a particular transcription factor is expressed in a cell? (2 ways)
1) TF in cell 1 regulated by a signal from cell 2 (Eg. morphogens) (non-autonomously)
2) TF in cell one can be regulated by an earlier-expressed TF in the same cell (autonomous)
What do the proteins of a cell determine?
- Behaviours of the cell (proliferation, migration)
- What circuits will occur, as proteins interact with each other (protein organisation)
- What the cell will look like (shape, type)
- What function the cell will have (receptor compliments, neurotransmitters made)
- Direct emergence of the cell
What builds the structure of the brain, CNS, PNS, behaviour and mind?
Proteins and their network assembly and function
What is differentiation?
Process at which cells become different from each other and acquire specific properties
What is differentiation governed by?
Changes in gene expression which dictate the repertoire of protein synthesised
