Stem Cells Flashcards
Describe cell differentiation
Different cell types result from differential expression in cells with the same DNA
Differences between cells in a multi-cellular organism come almost entirely from gene expression not differences in the cells’ genomes
These differences arise during development as regulatory mechanisms turn genes on and off
In nuclear transplantation
the nucleus of an unfertilized egg cell or zygote is replaced with the nucleus of a differentiated cell
What is SCNT? Give an example
Somatic cell nuclear transfer, used with dolly the sheep
What are the problems associated with animal cloning?
In most nuclear transplantation studies only a small percentage of cloned embryos have developed normally to birth
Ex. cloned mice are prone to obesity, pneumonia, liver failure, premature death
What are the reasons for the low efficiency of cloning?
Many epigenetic changes, such as acetylation of histones or methylation of DNA, must be reversed in the nucleus from a donor animal in order for the genes to be expressed or repressed appropriately for early stages of development
What is a histone modification
A covalent post-translational modification (PTM) to histone proteins such as : methylation, phosphorylation, acetylation, ubiquitylation
A stem cell is
A relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types
totipotent
ability to give rise to every type of cell in the adult body
ex. zygote
pluripotent
can form many different cell types
ex. embryonic stem cells (ESC) are pluripotent
Multipotent
ability to differentiate is limited to a few cell types
ex. bone marrow
What are IPSCs
Induced pluripotent stem cells are adult cells that have been genetically reprogrammed to an embryonic stem cell-like state by being forced to express genes and factors important for maintaining the defining properties of embryonic stem cells.
retrovirus
RNA virus that is replicated in a host cell via the enzyme reverse transcriptase to produce DNA from its RNA genome
What are some caveats of using retrovirus
Can cause mutations and or cancer
What is CRISPR
Clustered Regularly Interspersed Short Palindromic Repeats
Are segments of prokaryotic DNA containing short repetitions of base sequences that are interspaced with sequences derived from viruses. Each repetition is followed by a spacer DNA.
The CRISPR system can
be utilized as a tool to target location in complex mammalian genomes and generate site-specific breaks in DNA
