线粒体基因组.ppt

MitochondrialreplicationMitochondriareplicatemuchlikebacterialcells.Whentheygettoolarge,theyundergofission.Thisinvolvesafurrowingoftheinnerandthentheoutermembraneasifsomeonewaspinchingthemitochondrion.Thenthetwodaughtermitochondriasplit.Ofcourse,themitochondriamustfirstreplicatetheirDNA.Anelectronmicrographdepictingthefurrowingprocessisshowninthesefigures.Mitochondrialreplicationcelldivision:randomdistributionofmitosbetweendaughtercellsmitochondrialreplicationSometimesnewmitochondriaaresynthesizedincentresthatarerichinproteinsandpolyribosomesneededfortheirsynthesis.Theelectronmicrographinthefollowingfigureshowssuchacentre.Itappearsthattheclusterofmitochondriaaresittinginamatrixofproteinsandothermaterialsneededfortheirproduction.Certainmitochondrialproteinsareneededbeforethemitochondriacandivide.TheyshowedtheresultoftheremovalofanoutermembraneproteinfrommitochondriacalledMDM10.Thisfigureshowstheresults.Themitochondriaareabletotakeinponentsandproducemembranesandmatrixenzymes.However,fissionisnotallowedandtheresultisagiantmitochondrion.giantmitochondrionHumanmtDNA?small,doublestrandedcircularchromosome?16,569bpintotal?nonon-codingDNA?nointrons?polycistronicreplicationwhichisinitiatedfromtheD(displacement)-loopregion?followedbysplicingoftranscripttoformmessages.OrganisationofthemitochondrialchromosomehumanmtDNAYeastmitochondrialchromosomeyeastmtDNAHumanDNA?16,569bp;?nonon-codingDNA?nointrons?polycistronicreplicationfollowedbysplicingtoformmessages.YeastmtDNA?68-75kb,similarinstructuretobacterialgenome?containsintronsandnon-regionsbetweengenes.?Sameproteinsmadeasinanimals?genestranscribedseparatelyDespitehavingtheirowngenome,mostmitochondrialprotein