translational control and cellular communication Flashcards
how does translation happen in the pre- midblastula phase
dormant mRNA is stored in the oocyte. it is activated by the binding/ unbinding of proteins which enables translation
what is the effect of translation on the embryo
it can affect the embryos development, for example the anterior- posterior axis which develops as a result of mRNA already in the embryo
what does microRNAdo
it splices/ degrades the mRNA and is used in the transition from maternal mRNA to the zygotic genome
what is the effect of cell interaction
it gives different tissues specific properties and positional information via adhesion, gene expression and cytoskeletal changes
what are cadherins
transmembrane proteins. the intracellularly bind the cytoskeleton and extracellularly bind homophilically. different types or amounts segregate which causes boundaries
what are the two types of cell signalling
juxtracrine (direct cell- cell contact) and paracrine (indirect contact via ligands and receptors)
what is the role of the extracellular matric (ECM)
in influences behaviour of cells by binding to integrins which also bind intracellularly to the actin cytoskeleton (juxtacrine)
what is heterophilic binding
not to the same cell type. notch receptor binds ligand which enables the intracellular region of the notch receptor (transmembrane) to be cleaved. the cleaved portion enters the nucleus and activates transcription of the target gene (paracrine)
what are epithelial mesenchyme transitions
signals allow cells to detach from the basement membrane (ECM) and neighbouring cells, enabling them to leave the epithelium which is important for development
outline the basic paracrine mechanism
ligand binds to receptor, signal transduces, activates an effector eg TF, transcription altered eg FGF pathway
what are morphogens
one signal which can have multiple potential signal outcomes depending on the concentration of the morphogen eg activin, hedgehog
what are intracellular morphogens
they are rare as most are intracellular. an example is bicoid which has mRNA within the cell at the anterior end and is involved in the formation of the anterior- posterior axis
what are chemokines
small ligands which alter cell migration eg zebrafish germ cells migrate towards them
how is signalling affected (6)
movement of signal, ligand modification, exosomes, cytonemes, alternate downstream pathways and membrane dynamics
