This study examined the distribution and role of the Cadm1 protein in the mouse lens. The research found that Cadm1 is highly abundant in the epithelial cells and fiber cells of the one-month old wild-type lens. Cadm1 was also found to be equally present in the regular structured fiber cells of 2-3 day old wild-type lenses. However, lenses from Cadm1 knockout mice at this age showed disorganized membranes, indicating Cadm1 is important for maintaining lens cellular structure. The study concludes Cadm1 plays a key role in the lens and is found at highest levels in epithelial and fiber cell membranes.

1. 1

2. 3

3. • In humans, vision is the dominant
sense
• The sensory organ of vision is the
eye
4

4. • Is a complex organ which converts light
stimuli into electrical impulses
• Main parts of eye are:
– Eyeball
– Optic nerve
5

5. From: http://www.eyeclinic.ie/services/retinal-detachment.asp 6

6. Curved transparent organ in eye
The average size of lens in adult
human is 9 mm in diameter and 4
mm in thickness
Is composed of water (70%),
proteins (25%), and inorganic salts
(5%)
Function: accommodation, process of
variable focusing
of light on retina
FFrom: Bassnett gordon conference
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7. Mouse lens 8

8. Short-sightedness (myopia) Long-sightedness (hyperopia) Astigmatism
Blindness Cataract
9

9. • Most important and most abundant organic
molecules in living beings
• Composed of amino-acids according to DNA
code
• Diverse structures
(primary, secondary, tertiary and quarternary)
give them various functions in body
• Types of protein: enzymes, antibodies, some
hormones, …
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10. • The lens expresses
more than 200 kinds
of proteins
• The role of proteins
in the lens is
diverse: maintain
the
structure, transpare
ncy, enable
focusing, metabolis
m of the lens...
• Structural change
(denaturation): leads
Cadm1 Cell adhesion
molecule 1
to some diseases
e.g.cataracts 11
From: Steven Bassnett, Phillip A. Wilmarth, Larry L. David: The membrane proteome of the mouse lens fiber cell. Molecular Vision, 2009; 15:2448-2463

11. • Protein Cadm1 belongs to a group of cell
adhesion molecules
• Accounts for 11.7% of all lens membrane
proteins
• Roles of Cadm1 protein:
1) deficiency causes infertility in animals
2) in the brain connects neurons at synapses
3) found in breast cancer
4) deficiency leads to changes in the lens „?”

12. • The goal of my research was to
understand the distribution of protein
Cadm1 in the lens of the eye and to
examine its function
• My research was done at Washington
University in St. Louis (USA)
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From: http://www.criver.com/en-US/ProdServ/ByType/ResModOver/ResMod/Pages/Fox_Chase_SCID_Beige_Mice.aspx

15. Laboratory supplies Chemicals
Crytome Chemical mixtures
Sucrose
Vibratome Laboratory glassware
16

16. Immunofluorescence
Technique for localizing proteins
in a tissue using a combination
of primary and secondary
antibodies
Protein + primary antibody +
secondary antibody =
green areas on microscope
image
17
From: http://nobelprize.org/educational/physics/microscopes/fluorescence/preparation.html

17. Detection, distribution Cadm1 protein
(with antibodies)
Wild-type mice Knockout mice (lack Cadm1)
Rabbit anti-Cadm1 Rabbit anti-Mip
From: http://www.criver.com/en-US/ProdServ/ByType/ResModOver/ResMod/Pages/Fox_Chase_SCID_Beige_Mice.aspx

18. BSA

19. Cryotostat Vibratome
Microscope slides 20

20. Primary antibody Secondary antibody
Sealing preparations with varnish
21

21. Samples
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22. In my research I used two types
of microscope:
1. Fluorescence microscope
2. Confocal microscope
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23. Fluorescence
microscope
Preparation is
illuminated with a
specific wavelength
of light
The light is re-
emitted at a longer
wavelength
Finally, fluorescent
structures appear
bright against a
black background
24

24. Confocal
Uses a laser beam microscope
for illumination.
Collects a series of
optical sections that
can be used to
reconstruct the
specimen in three
dimensions.
25

25. Confirmed Cadm1 in the
lens of the eye
Large green regions in the
specimen indicate the presence
of Cadm1.
26

26. One-month-old wild-type lens
The ring of fluorescence
in the center of the lens
indicates that high
levels of Cadm1 were
produced in the first few
weeks of life (the oldest
lens cells are found in
the center of the tissue).
The picture was taken with
fluorescent microscope 27

27. Cadm1 expression in the epithelium
of one-month-old wild-type lenses
Protein Cadm1 is
highly abundant in the
membranes of
epithelial cells and
fiber cells.
The picture was taken with confocal
microscope
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28. Wild-type lens fiber cells (2-3 days old)
Regular structure of all
lens fiber cells in which
the presence of protein
Cadm1 is approximately
equal.
The picture was taken with confocal
microscope
29

29. Lens fibers of Cadm1 knockout mouse (2-3 days old)
are disorganized
Membranes are stained for
Mip, another abundant lens
membrane protein.
In the absence of Cadm1 lens
structure is disturbed.
The picture was taken with confocal
microscope 30

30. • Protein Cadm1 is found in specific
regions of the lens
• The highest levels of Cadm1 are
found in the lens epithelial and fiber
cell membranes
• Cadm1 plays an important role in
maintaining the cellular structure of
the lens
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31. Absence of Cadm1 in the lens causes
changes in structure of the lens fibers
Wild-type lens Cadm1 knockout lens
The pictures were taken with confocal microscope

32. Acknowledgements
 Dr. Steven Bassnett, mentor in USA
 Dr. Ksenija Kos for help with translation
 Mirjana Kežman, high school biology teacher
 My parents Lidija and Dražen, for their never -
ending encouragement and support.
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