Chromosome Structure Flashcards
What do errors in the centromere cause
Aberrant division
Chromosome instability
What is the centromere made up of
Repetitive satellite DNA making up 3 sub domains: CDE 1, 2, 3 and up to 20 different proteins
What types of DNA make up the centromere
Alpha DNA
Satellite 1, 2, 3
What’s so special about alpha DNA in the centromere
It’s a 171bp repeat, each of which is the binding site for CENP-B
What are the two types of proteins associated with the centromere
1) CENP-A, B, C: proteins constitutively associated with the centromere.
2) passenger proteins: proteins that are transiently associated during different phase of the cell cycle
Give an example of a passenger protein
ESCO2
SMC3
What group of disease are associated with passenger proteins of the centromere
Cohesinopathies
ESCO2: Roberts syndrome
SMC3: Cornelia de Lange
What’s a kinetochore
Large multiple protein (80) plate like structure
That assemble either side of the centromere and acts as a pint of attachment for spindle fibers
What’s a telomere
Highly conserved gene poor chromosome cap
What’s the role of the telomere
Maintain structural integrity (prevent sticky ends).
A role in the 3D architecture of the cell (positioning of chromosomes in the nucleus)
What’s the structure of the telomere
TTAGGG tandem repeats (3-20kb).
TAR (telomere associated repeats) (100-330kb).
Subtelomer (unique sequence)
What telomerase
Carries a TAGG antisense template to prime DNA synthesis on the leading strand to extend the telomere. This provides a template for the DNA polymerase to bind to to complete synthesis of the lagging strand
What NOR Stand for
Nucleolar organising region
Where is are the NOR
Stalks of the acrocentric: p12
What DNA do the NORs consist of
Satellite DNA 1, 2, 3, alpha and beta
