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SUMMARY:Post-transcriptional regulation of human mitochondrial gene expres
 sion - Michal Minczuk - MRC Mitochondrial Biology Unit
DTSTART:20111020T133000Z
DTEND:20111020T143000Z
UID:TALK32847@talks.cam.ac.uk
CONTACT:Becky Baglow
DESCRIPTION:It is estimated that 3 - 5 % of all human proteins are localis
 ed to mitochondria\, vital organelles that supply energy to the cell throu
 gh the process of oxidative phosphorylation (OXPHOS). However\, mitochondr
 ia are also involved in other important cellular processes such as Fe-S cl
 uster biosynthesis\, nucleotide biosynthesis\, calcium homoeostasis\, apop
 tosis or tumorigenesis.\nApproximately 90 proteins form the five enzyme co
 mplexes that perform OXPHOS and 13 of those are encoded in the mitochondri
 al genome - circular\, multicopy (up to 1000 copies per cell)\, 16.5-kb mo
 lecule often referred as mtDNA. For this reason mitochondria contain a sep
 arate genetic system\, necessary for the expression of the mtDNA-encoded p
 olypeptides of the OXPHOS system. Transcription of both strands of mtDNA y
 ields precursor polycistronic RNAs\, from which the full panoply of mature
  mitochondrial transcripts is generated. Processed mitochondrial mRNAs are
  polyadenylated and in many instances the addition of the poly(A) tail is 
 required to complete stop codon\, however the exact function of human mito
 chondrial poly(A) tails is unclear. In addition to the mRNAs coding for th
 e respiratory chain subunits\, the mitochondrial genome also encodes 2 rRN
 As and 22 tRNAs that are required for intra-mitochondrial protein synthesi
 s by dedicated ribosomes (mitoribosomes). All protein components involved 
 in mitochondrial gene expression including RNA polymerase\, transcription 
 factors\, RNA processing enzymes\, mitochondrial ribosomal subunits\, tran
 slation factors et al. are encoded by nuclear genes and imported to mitoch
 ondria from the cytosol.\nCurrently\, we try to understand the regulation 
 of mitochondrial gene expression. We focus on identifying and isolating ne
 w factors that are important for the post-transcriptional stages of mitoch
 ondrial gene expression. During my talk I will describe our recent work on
  proteins regulating mitochondrial RNA polyadenylation and mitoribosome bi
 ogenesis. 
LOCATION:Part II room\,  Department of Genetics
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