Cell Differentiation Flashcards
pattern formation
process by which cells in a developing embryo acquire identities that lead to the formation of distinct regions/functional entities
specification
group of cells is specified if when isolated in cultures they develop according to their normal fate; reversible
determination
implies stable change in the state of a cell such that the fate is now fixed; irreversible
stuff Weismann postulated
chromosomes control development; chromosomes make nuclear determinants; different cell types inherit different determinants as the embryo divides
Gurdon
demonstrated that nuclei of differentiated cells retain their full genomic content; laid foundation for animal cloning
RNA Seq (shotgun sequencing)
extract RNAs from cell, select for mRNAs; convert mRNAs to cDNA
histones
protein component of chromatin
nucleosomes
basic unit of chromatin structure composed of an octamer of histone proteins wrapped with 2 loops of DNA
methylated histone
closed DNA
acetylated histone
open DNA
DNA can be directly methylated on _______ residues
cytosine
methylcytosines
facilitate binding of proteins that catalyze the methylation or deacetylation of histones; prevent TFs from binding to enhancers
Chlp-Seq assay
- chromatin isolated from cell
- TFs are crosslinked to their DNA binding sites
- antibodies bind to specific chromatin proteins
- antibodies are precipitated out of solution
- DNA frags associated with precip complexes are purified and sequenced
- DNA sequences are compared with genome maps
events of transcription
PIC must form on promoter plus RNA poly; mediator complex initiates a chromatin loop bridging the enhancers to the promoter region; cell specific TFs bind to enhancer
domains of TFs
- DNA binding domain
- transcription activation domain
- optional interaction domain for interacting with other TFs
how are TFs asymmetrically distributed?
- localized molecule tethering/stabilization of molecule transport
- cytokinesis
requirements for TFs to be asymmetrically distributed
mother cell must be polarized; mitotic spindle must be aligned with the axis of polarity
changes in protein activity in cytoplasm from inductive signaling
electrical properties of cell; adhesive properties of cell; shape, migration, programmed cell death
changes in gene expression in nucleus from inductive signaling
cell division, cell fate
endocrine
uses bloodstream; physiological control
juxtacrine
signal is bound to surface of sending cell and can only affect neighboring cells
autocrine
when signalling cell and responding cell are of the same type
paracrine
signals released into space between cells
