Bio 1-L17- Appropriate Cell Differentiation and the Importance of time and Space

WHAT IS IMPORTANT FOR CELL DIFFERENTIATION

• time- notch signalling- differentiation is progressive and coordinated

• space- hippo- positional information

how is gene expression detected in the embryo

• presence of mRNA

• transcriptonomics

• in SITU HYBRIDSATION

what is in situ hybridisation

• visualises when ad where master control genes and expressed

• detects mana WITHIN CELLS- WITH A PROBE- or use reporter genes such as GFP

when is a cells fate decided- is this time or space

• it can no longer respond to changing environmental signals and change its pathway

difference between specification and determination

• specification- early commitment- but still can be reversed

• determination- has fixed its fate

what is lateral inhibition

ensures all cells in a similar field of cells do not undergo differentiation at the same time

delta notch pathway example

• how cell decides to become a neuron or not- JUXTACRINE

• if one cells expressed more delta than notch- becomes neuroblast and inhibits cells around it

how do cells receive positional information- SPACE

• asymmetrical cell division- different daughter cels

• induction- cell-cell signalling

what is a morphogen

a signal involved in pattern formation- cells have a graded response depending on level it is exposed to

examples of morphogens

• bicoid in drosophila- role in axis establishment

biophysical envirmnet- what can this also give?

• positional information

• ie when humans move less as a fetus- fractures and thin bones

hippo signalling pathway- yap/taz

• if yap/taz enter nucleus- has cell proliferation

• if yap/taz phsoprylated it cannot control gene expression

• wild type- smaller, mutated- bigger increased size