Sub-nuclear Structures Flashcards
What are the three major components of the nucleolus?
Fibrillar centres (FC), dense fibrillar components (DFC) and granular components (GC).
What is the nucleolus composed off?
Proteins and Nucleic acids
What are the three types of nuclear proteins?
Those mostly in the nucleolus: fibrillarin and nucleolin.
Those partially in the nucleolus: ribosomal proteins.
Time/condition dependent: p68 and cell cycle factors.
What is the pivotal role of the nucleolus?
Ribosome biogenesis.
What are ribosomopathies?
A collection of disorders I’m which abnormalities cause impaired ribosome biogenesis.
Give the three ribosomopathies?
Diamond-Blackman Anemia, treacher Collins syndrome, dyskeratosis congenital.
What is the mutation in diamond-blackman Anemia?
Mutation in ribosomal protein S19.
What are the symptoms of diamond-Blackman anaemia?
Low red blood cell count lead to a variety of congenital abnormalities. Craniofacial malformations, upper limb abnormalities, cardiac defects.
What is the mutation in treacher Collins syndrome?
TCOF1 gene mutation, which encodes a nucleolar protein treacle.
What are the craniofacial deformities in treacher Collins syndrome?
Absent cheekbones, a small lower jaw and malformed or absent ears.
What is the mutation in dyskeratosis congenital?
Mutation in DKC1, which encodes dyskerin.
What are the symptoms of dyskeratosis congenital?
Progeria.
What are many nucleolus associated diseases associated with?
Changes in ribosome biogenesis and sequestration or loss of proteins.
What are the two links between ribosomes and cancer?
Increased ribosome biogenesis (satisfies deman in proliferation, evidence of proto-oncogenes can up regulate ribosome biogenesis) and deficiencies in ribosome function.
What is c-Myc?
A proto-oncogene which is up-regulated in a variety of leukaemia’s and solid tumours.