The SubNucleus Flashcards
Which compartment do ribosomopathies effect?
Nucleolus
What mutation causes diamond black fan anaemia?
S19 ribosomal protein
Which diseases are ribosomopathies?
Diamond-blackfan anaemia
Treacher collins syndrome
Dyskeratosis congenita
What mutation does dyskeratosis congenita have?
DKC1 gene mutation encodes dyskerin snoRNP associated protein
What is the phenotype of dyskeratosis congenita?
Ageing
Spinal muscular atrophy has mutated SMN protein in which compartment?
Cajal and gem bodies
Which viruses target nucleoli?
Coronavirus removes translation factor to cytoplasm
Herpes virus replicates in nucleus, altering proteasome
Spinal muscular atrophy effects which cells?
Motor neurones in anterior spinal horn
What causes retinis pigmentosa?
Mutation of PRP13 splicing factor causing loss of rods and cones
Retinoic-acid-receptor-alpha is mutated in what disease?
Acute promyelocytic leukaemia
What happens in acute promyelocytic leukaemia?
PML bodies are fused with RARa gene
What is the ribosome biogenesis pathway?
rRNA transcribed from tandem repeats in fibrillar centre
45S pre-rRNA processed by snoRNPs in dense fibrillar component to produce 28S, 5S, 5.8S, 18S
Granular component assembles ribosome subunits
What is the nucleolus?
A large multiprotein hub of 4500 proteins
Fluctuations based on cell cycle
How is the nucleolus implicated in cancer?
SIze changes
Upregulation of ribosome biosynthesis
Downregulation of ribosome synthesis in tumour supressors
Why do viruses target the nucloelus?
Subvert immune response
Hijack machinery for replication
How is the spliceosome assembled?
Gems contain SMN protein
Adjacent Cajal body uses SMN and coilin to synthesise snRNA
Nuclear speckles in interchromatin act as stores of snRNPs for maturation
What are the splicing-associated diseases?
Spinal muscular atrophy
Retinitis pigmentosa
What are Polycomb bodies?
Hubs for gene repression
What is the function of PML bodies?
Respond to cellular stress as a promiscuous modification factory
What is the structure of PML bodies?
10-30 per cell
0.1-1µm
self assembly/nucleation of monomers
recruits SUMO proteins
Why are PML bodies targetted by viruses?
Subversion/no maturation of granulocytes
