Mitochondrial DNA Flashcards
what are the main elements of the mt genome?
non-coding D loop, HSP, LSP, OH, OL
why do mt genomes vary in size between species?
number of introns and genes encoded
copy number in somatic and copy number in oocytes
20-200 and 200,000
what is different in bacterial mt genomes?
has variation in triplet code
what ETC complex is just encoded by nuclear DNA?
complex 2
what needs to be transcribed for transcription to occur?
section of LSP
nuclear encoded things required for replication
transcription factors, co factors and polymerases
how does TFAM work?
binds LSP and transcribes entire light strand and generates RNA primer for replication. RNA/DNA transition, then replication of OH from HSP and replication of light strand once OL exposed
the only mt polymerase
PolG
what happens when TFAM knocked out?
homozygous= severe mtDNA depletion, abolished OXPHOS, enlarged mt, growth retardation, lethal at E10.5
in heterozygotes= reduced mtDNA copy number, transcription and get respiratory chain dysfunction
overall what is the role of TFAM?
maintain mtDNA copy number and respiratory chain function. Also essential for replication of mtDNA. Also may have packaging role in nucleoids
why are nucleoids important?
they regulate stability, replication, transcription and segregation of mtDNA
what does TFAM binding do to DNA?
binds LSP and HSP and bends it into a U shape
how many nuclear encoded products are essential for mt function?
over 1000
