Mutations in Paramecium CaM Indicate Functional Differences bw the CTerminal

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Mutations in Paramecium CaM Indicate Functional
Differences b/w the C-Terminal N- Terminal
Lobes In Vivo
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JA Kink, ME Maley, RR Preston, KY Ling, MA
Wallen-Friedman, Y Saimi C Kung

• Ashim Malhotra
• October 27, 2003

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Lay Out

• Background Introduction
• CaM Structure Rasmol
• Experimentations
• Conclusions
• Philosophy Trends

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Calmodulin

• 148 amino acid long protein with 4 calcium ion
  binding pockets-I, II, III, IV.
• III IV in C-terminal loop I II in
  N-terminal loop.
• Mediates many Ca signaling pathways.
• Ca ion binding causes a closed conformation
  with hydrophobic domains inaccessible to targets.

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Calmodulin Structure
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www.angelfire.com/d20/bio_lab
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Paramecium Movement
http//micro.magnet.fsu.edu/moviegallery/pondscum/
protozoa/paramecium/
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Immunoblots of Mutant wt CaMs
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Nucleotide Sequence of P. tetraurelia CaM gene
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Analysis of Paramecium CaM gene
Northern Blot
Southern Blot
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Amino Acid Sequence of wt Mutant CaM genes
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Effect of CaM Mutations on Na Behavior Ca2
Currents
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Ca2 -Dependent Na Current Ca2 - Dependent
K Current of wt, Cam3 Cam12 Strains of P.
teraurelia
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CaM Electrophoretic Mobilities Cosegregate w/
Behavioral Phenotypes among Autogamous F2
Segregants
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Conclusions

• CaM mutation may not be lethal, instead it may
  cause behavioral/functional mutations.
• In P. tetraurelia, behavior may be directly
  influenced by genetic mutations- the genetic
  dissection method for studying mutational
  effects.
• The over-reactor mutants carry mutations in
  amino terminal half of CaM gene.

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Conclusions (contd)

• The under-reactor mutants carry mutations in
  C-terminal half of the gene.
• The under-reactors show low inward Ca2
  -Dependent Na Currents.
• The over-reactors show low Ca2 - Dependent K
  Currents.

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The Philosophy

• Functional or behavioral responses have a genetic
  origin anthropological approaches for studying
  human development, particularly of intelligence.
• A molecular phenomenology sited as causative link
  in an evolutionary process.

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• Thank You