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C. elegans as a model organism
Kavya Leo Vakkayil
20101080, BS-MS
IISER PUNE
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GROWTH OF A RESEARCH AREA
Jonathan Hodgkin, University of Oxford
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1. An introduction to C. elegans
• Anatomy
• Life cycle
2. A short history of C. elegans research
3. Advantages and applications of C. elegans
4. C. elegans in biology@IISER PUNE
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C. elegans
• Small, free living(non-parasitic)soil nematode
• Survives by feeding on bacteria
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C. elegans
TWO SEXES:
1. A self fertilizing hermaphrodite(XX)
2. A male(X0)
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ADULT ANATOMY
A. DIC image of an adult hermaphrodite, left lateral side. Scale bar 0.1
mm. B. Schematic drawing of anatomical structures
A. Schematic drawing of anatomical structures, left lateral side. B. DIC
image of an adult male, left lateral side. Scale bar 0.1 mm
C. The unilobed distal gonad of the animal in B is shown as enlarged. D.
The adult male tail, ventral view. (Arrow) Cloaca; (arrowhead) fan. Rays
1-9 are labeled with asterisks on the right side.
E. L3 tail, bottom, starting to bulge
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LIFE CYCLE
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A SHORT HISTORY OF C. elegans RESEARCH
• Developed by Sydney Brenner(1963).
• Mutants published by Brenner(1974).
• Post embryonic cell lineages determined (Sulston and Horwitz,1976).
• Programmed cell death( Horwitz, 1982).
• Complete embryonic cell lineages determined( Deppe et al, Sulston 1983).
• Complete connectivity of nervous system was established(1986).
• RNAi and miRNA discovered in worms(1991-98)(Nobel Prize: Fire, Mello 2006).
• First use of GFP in animals(1994) (Nobel Prize: Chalfie, 2008).
• First animal whose whole genome was sequenced(97Mb,now 100.3Mb).
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A SHORT HISTORY OF C. elegans RESEARCH
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ADVANTAGES OF C. elegans AS A RESEARCH TOOL
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Simple
Easy to grow
Short life cycle
Powerful genetic studies can be conducted(Both self fertile and cross fertile)
Transparent
Small
Invariant cell lineage
Fully described anatomy and development
Completely sequenced genome
Tools like RNAi knockdowns can be performed
Stocks can be frozen and preserved
No expensive animal house costs, CHEAP TO MAINTAIN!
Present no biohazard
Large size of progeny
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APPLICATIONS IN VARIOUS BIOLOGICAL RESEARCH AREAS
1. Developmental biology and Cell biology
• Transparency helps to view anatomy and development.
• Individual cell lineages can be easily traced and directly inspected by
DIC light microscopy.
• Programmed cell death can also be visualized.
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• Specific cells, cellular architecture can be directly examined using reporters like
Green fluorescent protein(GFP)* .
Ilys genes(lysozyme) exhibit distinct patterns of pharyngeal
expression.
*GFP= GREEN FLUORESCENT PROTEIN .Small protein derived from luminous jelly fish and can
be introduced as a transgenic tag to mark any protein in the animal.
Jonathan Hodgkin, University of Oxford
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2. Neurobiology
• Act as a model for neuronal development and function.
• No brain per say, but have sophisticated nervous system(302neurons/959 cells).
• C. elegans responds to chemo attractants/repellants.
• Laser beams(selective cutting of neurons) and electrophysiology studies can
be conducted.
• Connectome (the complete wiring diagram) have been established.
3. Aging
• Short life span helps to conduct genetic screens to find longevity genes.
4. Human disease studies
• ~75% of human disease genes have potential C. elegans homologs.
• ~40-50% have a C. elegans ortholog.
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C. elegans RESEARCH IN IISER PUNE
Biochemical and genetic characterization of chromatin organizer protein Dve-1
and its role in C. elegans development and aging.
The present study seeks to elucidate the mechanism by which chromatin
organization impacts organismal aging by studying C. elegans protein (Defective
proventriculus) Dve-1.
• Identify genetic and physical interactors of C. elegans Dve1.
• Generate C. elegans strains mutated in Dve1 and characterize the function of
Dve1 during C. elegans development and aging.
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THANK YOU
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