gene structure/expression Flashcards
(17 cards)
what is gene expression, what does the regulation of gene expression determine, what is a gene
gene expression=products of genes produced from genome under particular circumstances
-regulation of gene expression determines which genes are producing protein/RNA products
gene=DNA region transcribed to produce product
level of expression is maintained by…
what is homeostasis
level of expression is maintained by synthesis and degradation
-changing a cell requires changing the synthesis or decay of specific proteins and RNAs
homeostasis=state in which a cell appears to be unchanging
what are the main classes that make regulation of gene expression specific for a particular gene
- DNA binding transcription factors-regulates transcription
- RNA binding proteins-regulate every part of mRNA from processing→translating→decay
- small nuclear RNAs-mediate processing of RNAs in nucleus esp splicing
- microRNAs-regulate mRNA stability and translation and E3 ubiquitin ligases which target proteins for decay
complex structure of human protein coding gene allows…
-production of multiple proteins from one gene
-finer control of where and when proteins are produced
how do RNAs recognise other RNAs
by base pairing, bind proteins and catalyse chemical reactions (ribozymes)
DNA and RNA contain many regulatory sequences, sequences close to protein coding regions regulate what
the amount of protein produced
what regulates transcription and mRNA translation and stability
-transcription is regulated by protein that binds to the DNA and alter the chromatin
-mRNA translation and stability is regulated by proteins that bind to the mRNA
location of regulatory sequences are specific, where are the regulatory sequences for transcription, mRNA stability, translation and protein decay
transcription=promoters are close to transcription start site, enhancers can be long distances away on the same chromosome
mRNA stability=generally in 3’ untranslated region, sometimes in coding region including codon usage
-eg. microRNAs work by binding to 3’ untranslated regions
translation=in 5’ and 3’ untranslated region, and including coding region
protein decay=in coding region
regulatory regions and non-coding RNAs are great potential drug targets for nucleic acid therapy bc…
easy to design specific binding through base paring
alternative splicing allows…
production of functionally distinct proteins from the same gene
what does high throughput sequencing allow
identification of splice forms specific to cancer
VEGF-A gene produces 2 proteins with opposite effects, what is one variant, what does that encode and how is it generated
VEGFA-B
encodes anti angiogenic peptides
generated by alternative 3’ splice sites in exon 7
what is splicing
removal of introns/noncoding regions
mutations in splicing factors are common in…
myeloid displasia
specific splice events can be targeted with…
nucleic acid therapy
cancer cells with MYC overexpression are more…, splicing in cancer cells become…
dependent on efficient splicing
becomes more abnormal and produces different forms of proteins that can promote cancer growth/survival/drug resistance
what is alternate splicing and what is the results of it
different combinations of exons joining to produce multiple mRNAs from one gene leading to variants
in cancer, leads to production of oncogenic proteins or disabling tumour suppressors
-adds/removes domains from RNAs and proteins=changing function
