CSB329H1 Lecture Notes - Lecture 5: Neuroglia, Retina, Crispr
9 May 2018
School
Department
Course
Professor
Lecture 5: Zebrafish- Retinal Stem Cells
Development:
• Initial 48 hours of development the zebra fish are completely transparent
(very beneficial for live microscopy)
o Localized on top of a ‘ball of yolk’ – for 5-6 days, animal relies entirely on the contents
of the yolk as a source of nutrients for development
ð Retinal Development:
o ~12 hours post fertilization: retina disk is not visible
o ~24 hours post fertilization: retina disk is transformed
(lens is visible); pigmented cells are differentiating
o ~4 days post fertilization: retina is full with pigment cells
Retinal Stem Cells:
• Retinal stem cells are the source of retinal development and homeostasis
o Somatic Stem Cells (i.e. retinal, brain, muscle…)
3 Defining Features of Somatic Stem Cells:
a) Self-Renewal
b) Tissue specific multi-potentiality
c) Longevity
Embryonic Neurogenesis:
• Period of neurogenesis occurs from Day 1 to Day 3 during
embryonic development; 48 hours
o Within 48 hours basic functioning retina is
established
§ Retina was previously filled with stem-cells; now is filled with differentiated
mature cells (stem-cells are highly active during this period)
ð Organization of mature retina is highly conserved among vertebrates
Retinal Stem Cell Differentiation:
• 24-hours post fertilization:
o Retina only consists of retinal stem cells
• 48-hours post fertilization:
o Some stem cells are exiting the cell-cycle and
become post-mitotic retinal progenitor cells
• 72-hours post fertilization:
o Progenitor cells begin to differentiate into neuronal and glial cells
§ Vast majority of the central retina is differentiated;
central-to-peripheral wave of differentiation
ð Stem-cells are found in pockets on the edge of the retina; around the iris of the eye (periphery)
Document Summary
Retinal development: ~12 hours post fertilization: retina disk is not visible, ~24 hours post fertilization: retina disk is transformed (lens is visible); pigmented cells are differentiating, ~4 days post fertilization: retina is full with pigment cells. Retinal stem cells: retinal stem cells are the source of retinal development and homeostasis, somatic stem cells (i. e. retinal, brain, muscle ) 3 defining features of somatic stem cells: self-renewal, tissue specific multi-potentiality, longevity. Embryonic neurogenesis: period of neurogenesis occurs from day 1 to day 3 during embryonic development; 48 hours, within 48 hours basic functioning retina is established. Retina was previously filled with stem-cells; now is filled with differentiated mature cells (stem-cells are highly active during this period) Organization of mature retina is highly conserved among vertebrates. Vast majority of the central retina is differentiated; central-to-peripheral wave of differentiation. Stem-cells are found in pockets on the edge of the retina; around the iris of the eye (periphery)
