Online Molecular Genetics Review

Honors Biology 2013-2014

snRNPs

• snRNPs, or small nuclear ribonucleic particles, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs. ...

Joseph Merrick (1862-1890)“The Elephant Man”

• Originally believed to be afflicted with maternal impression as his mother was frightened by an elephant when pregnant with Joseph• Actual cause of affliction was

Proteus syndrome (mutation of ATK1 gene on chromosome 14)• Was put on display in London

Hospital • Died of asphyxia in 1890 due to

the weight of his cranium

Neurofibromatosis (NF)• Caused by mutation in

neurofibromin gene (chromosome 17)• Neurofibromin controls the

activity of the RAS gene, which causes nervous tissue to divide• Frequency 1:3,000 births• Result: uncontrolled division

of neural tissue

Different Types of NeurofibromatosisInherited De Novo

•Due to a spontaneous mutation in chromosome 17•50% of cases of NF-1

are de novo

How is Neurofibromatosis similar to Achondroplasia in regard to the

mechanism of its molecular genetics?

Five Different De Novo Mutations of the Neurofibromin (NF-1) GeneMutant Sequences 1,2,3 & 5

• Cannot stop the RAS gene from causing rapid cell division

Mutant #4

• Despite mutations, #4 is able to prevent the RAS gene from promoting rapid cell growth

The Cure For Neurofibromatosis?• None (yet)

Why is it unlikely that there will ever be a single cure for neurofibromatosis?

Five different NF-1 Mutations = Five Different Causes of Neurofibromatosis

What were the contributions of…

•Avery•Chargaff•Griffith•Miescher•Levine•Watson & Crick•Wilkins & Franklin

What is timing, purpose and process

• REPLICATION• TRANSCRIPTION• TRANSLATION

COMPARE & CONTRAST

•Strength, purpose and location of•Phosphodiester bonds•Hydrogen bonds•Peptide bonds