* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Eukaryotic Gene Expression
Secreted frizzled-related protein 1 wikipedia , lookup
Non-coding RNA wikipedia , lookup
Epitranscriptome wikipedia , lookup
RNA polymerase II holoenzyme wikipedia , lookup
X-inactivation wikipedia , lookup
Gene expression profiling wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Molecular cloning wikipedia , lookup
Genome evolution wikipedia , lookup
List of types of proteins wikipedia , lookup
Community fingerprinting wikipedia , lookup
Molecular evolution wikipedia , lookup
Eukaryotic transcription wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Gene regulatory network wikipedia , lookup
Histone acetylation and deacetylation wikipedia , lookup
Non-coding DNA wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Endogenous retrovirus wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Gene expression wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Eukaryotic Gene Expression • Why is gene regulation more complex in eukaryotes than prokaryotes? • Eukaryotes have larger more complex genome • Eukaryotic DNA must be more highly organized than prokaryotic DNA Prokaryotic vs. Eukaryotic DNA • • • • Prokaryotic DNA circular smaller than eukaryotic DNA associated with very few proteins less structured and folded Eukaryotic DNA • associated with lots of histone proteins to form chromatin fiber • very extended and tangled during interphase • condensed into discrete chromosomes during mitosis Eukaryotic Development • Cellular differentiation is the specialization of cells during development • Since all cells have the same DNA, how can differentiation occur? • Gene regulation. Selective Gene Expression • How do cells become specialized? • Different genes are activated at different times during development. • Each cell utilizes only about 3% of genome DNA Packing Helps regulate gene expression • DNA in one human cell’s 46 chromosomes would be 3 meters long. • How, then, does it all fit into the nucleus? • DNA packing • Why do densely packed regions of chromosomes inactivate gene expression? • RNA pol can’t get to the gene for transcription. • What is the difference between heterochromatin and euchromatin? • Heterochromatin remains highly condensed even during interphase • Barr bodies are X chromosomes condensed into heterochromatin • Telomeres, centromeres also heterochromatin • euchromatin is chromatin that is not condensed and can be transcribed Control of Gene Expression • What are the steps from chromosome to functional protein? • Unpacking Transcription mRNA processing export from the nucleus translation protein modification • ANY of these steps can be regulated in eukaryotes Control of Gene Expression Chromatin modification • DNA methylation; the addition of methyl groups to DNA • essential for inactivation of the DNA – Inactive genes in a cell are methylated – Epigenetic memory due to methylating enzymes that methylate the new daughter strand the same as the parent strand. • Can be passed on in repro • Histone acetylation is the attachment of an acetyl group to histone proteins • acetylation increases likelihood for transcription of the DNA Transcriptional Control • Transcription factors allow RNA pol to find the promoter region • association between transcriptional factors and enhancer or promoter region regulates gene expression Posttranscriptional control • Regulation of RNA processing • Regulation of mRNA degradation – Can last from hours to weeks • Regulation of translation – initiation sequence can be blocked Protein Degradation; posttranslational control