Intro to Control Of Gene Expression Flashcards
What is genotype?
Human cells all contain same genetic blueprint
Differential gene expression is regulated in:
Time= development, in response to hormones, infections + other signals Space= different tissue or cell type express different genes
Failure to regulate gene expression may lead to:
Metabolism=> metabolic disease
Cell shape motility=> metastasis
Cell differentiation=> congenital disorders
Cell proliferation=> Cancer
What is definition of totipotent cells?
Found in zygote + differentiate into any type of cells in organism
What is definition of pluripotent cells?
Give rise to all tissues in body except placental tissues
What is reprogramming?
We can take a cell like skin cell and we can reprogram it to give rise to pluripotent stem cells => it works by using transcription factors
What is B-thalassaemia?
Group of genetic diseases caused by insufficient expression of b-globin
Give examples of translational control?
Early embryogenesis (formation of embryo) environmental stress=> exposure to heat shock of pathogens can cause global changes in translation Many specific examples-e.g. ferritin
Describe the anatomy of eukaryotic mRNA
5’ UTR is part of exon 1 but it is not translated
Frame is set by first codon which is always an AUG
Kozak sequence is sequence of that is part of 5’ UTRs therefore it is not translated
Initiation of polypeptide synthesis is by……
eIF= eukaryotic initiation factors
elF3 +elF4 regulate whether we will have more or less binding of ribosome
What is role of 5’ UTR?
Determine whether ribosome binds + play a role in determining how efficiently ribosome initiates translation
Globin is very……translated
Efficiently
Ferritin is very …….. translated
Inefficiently
Binds to iron + retains in cytoplasm as store for excess iron
What happens in Fe starvation?
mRNA is not translated into protein
Cap is still present
Ribosomal small subunit cannot move along the ferritin mRNA
5’ UTR forms hairpin as there is some not complementary bases that forms loop
This can be recognised by inhibitor=> prevents ribosome moving along mRNA therefore no translation
What happens in Fe excess?
Cell expresses ferritin
Iron molecule will bind to inhibitor=> as result this inhibitor is now different + can no longer bind to loop
Ribosome can move along mRNA + it can be translated into ferritin protein
