Differential gene expression Flashcards
How many cells make up the human body and how many cell types are there
37 trillion cells; about 200 different cells types
Neurons are how long
3 feet long
He won the Nobel prize 1965 for his contributions to the genetic control of enzyme and virus synthesis.
Jacques Monod
every somatic cell in one’s body contains the same chromosomes, and if they contain the same chromosomes, then they may possibly contain the potential to in fact give rise or become any cell in our body
Concept of genomic equivalence
Sir Ian Wilmut and his colleagues produced the first viable animal cloned from a somatic cell nucleus in 1997 using ________to incorporate the nucleus of a differentiated udder cell from a six-year-old adult sheep into an enucleated egg (an oocyte lacking a nucleus). The resulting blastocyst was implanted into a surrogate sheep - > Dolly was born, survived, and reproduced naturally, herself.
somatic cell nucleotransfer
_______ can stimulate transcription while ________ can inhibit transcription.
Enhancer domain; repressor domain
_____ base pairs of DNAs are complexed with __ histones, forming a nucleosome and these nucleosome structures are regularly repeated about every ____ base pairs throughout the genome.
147; 8; 70
When DNA is coiled around histones and tightly packaged, it forms _______ during which access to genes is closed. However, when the coiling is loosened, it takes on a form or state called ________, and access to genes for transcription is opened.
heterochromatin; euchromatin
Gaining access to DNA for transcription requires an open promoter region.
If the methyl groups in the nucleosome are removed and replaced with acetyl groups on those tails, then an uncondensed nucleosome structure will be established. Acetylation often promotes access and active transcription in that particular region of the genome, while most methylations will serve to condense chromatin and repress transcription.
Loss of the gene _______ , a homeobox containing transcription factor, causes a complete change in the segmentation pattern in the fly. Such that it forms two sets of perfectly developed wings in the wrong location.
ultrabithorax
_________ are migratory stem cells- they leave the nervous system and venture throughout the embryo to populate a variety of tissues and differentiate into a variety of different cell types (pigment cells, cartilage cells, sensory neurons).
Neural crest cells
_________ and _________ are 2 of the most significant ways in which gene expression can be regulated, so precise in timing, space, and amount.
Chromatin modification; transcription factor binding into cis-regulatory elements
Mutations in the coding regions of genes have not really been the driving force of evolution but rather _____________ has provided a mechanism to subtly change gene expression patterns in a developing embryo without having to alter the function of that protein.
duplication and mutation in the cis-regulatory elements of a gene
Ways to regulate genes and proteins that influence how cells differentiate:
- Methylation of DNA
- Alternative splicing of RNA
- Proteins can be modified with residues
- Proteins can be restricted by location
- Protein can be degraded directly.
How long can we arrest a stem cell so it doesn’t differentiate into a specialized cell and therefore be used for treatment later on?
Most stem cells have indefinite maintenance is possible if cultured in the right conditions with essential growth factors
Do we have the technology to turn off and on a gene immediately so a potential problem in the development of an organism will be halted or even at least mitigated?
a. Tet-On/Tet-Off System (Tetracycline-Controlled Gene Expression)
b. Optogenetics (Light-Controlled Gene Expression)
c. Heat-Inducible Systems (Temperature-Sensitive Gene Regulation)
a. CRISPRi (CRISPR Interference - Gene Silencing)
a. RNA Interference (RNAi)
