ppt课件-国外大学细胞生物学ppt课件-英文9.bioy.ppt

Mitochondrial Diseases W2011 D103 Cell Biology – lecture 9 - Suetterlin and MacGregor: all rights reserved. * Diseases result from inherited or spontaneous mutations that affect mitochondrial energy production ? Affect multiple organs but often more pronounced in tissues with high energy requirement (eg heart, brain and muscle) Mutations can occur in mtDNA, in nDNA or in both. Unique considerations for mitochondrial diseases: ? Heteroplasmy: more than one type of mt DNA in an individual (wt and mutant forms) ? variable distribution in different cells or tissues ? Threshold effect (% of mutant mtDNA must be above threshold to produce clinical phenotype, this may be different between tissues, dependent on energy requirement) ? Hallmark of mitochondrial diseases: Identical mtDNA mutations may not produce identical diseases. /bin/view/MITOMAP * COMPLEX I 39 subunits (nDNA) 7 subunits (mtDNA) mtDNA Nuclear DNA mutation Leigh’s syndrome mtDNA mutation Leber Disease (LHON) Diseases associated with mutations in genes that encode for subunits of complex I mtDNA nDNA W2011 D103 Cell Biology – lecture 9 - Suetterlin and MacGregor: all rights reserved. Degeneration of the central nervous system (autosomal recessive inheritance) Acute or subacute loss of central vision (maternal inheritance) * Oxidative phosphorylation Electrons (from NADH and FADH2) move down the electon transport chain, leading to the establishment of a electrochemical proton gradient, which is used to generate ATP ATP synthesis requires a tight, proton impermeable inner mito membrane Mitochondria cell biology contain 2 functionally distinct membranes with specialized composition and function (porins in outer membrane, cardiolipin in inner membrane) contain their own DNA encoding for 37 genes - replicated, transcribed and translated in the mitochondria - Most mito activities depend on protein and RNA import from the cytosol adapt to a cell’s energy requirement in respect to their sh