& cell biology perspective opportunity, throughout- microtubules and motors calcium mediated...
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&Cell biology perspective opportunity, throughout-
Microtubules and motorsCalcium mediated Membrane fusions Cell-Cell interaction – First example
Gametogenesis
and Fertilization Unit
Gametogenesis (Germ cell specification and maturation)
• Germ line specification (g.l. stem cells first)
• Germ line migration to the gonads
• Meiosis
• Gamete maturation
Figure 2.1 Developmental History of the Leopard Frog, Rana pipiens
Set aside as quiescent cells.“Pole cells”, with “pole plasm” Transcription & Diff. to Ecto,Meso, Endo blocked
For All Bilaterians (here, ecto-meso-endo specifics for tetrapods)
Set aside as quiescent cells. These express Vasa in all bilaterians. & Nanos, Piwi. . .
For All Bilaterians:
For All Bilaterians:
For All Bilaterians:
For All Bilaterians: In addition ‘placement’ in the proper positions - -
These molecules are transported on microtubules (made of Tubulin)
as cargo on molecular motors:
see Movies: Kinesin_Transport_Protein.MOV
Dynenin: to -Kinesin: to +
For All Bilaterians:
Vasa and Nanos- RNA binding proteins
In flies and many others:
Figure 2.21 Major Evolutionary Divergences in Extant Animals
Gametogenesis (Germ cell specification and maturation)
• Germ line specification (g.l. stem cells first)
• Germ line migration to the gonads
• Meiosis
• Gamete maturation
Mammalian
Zebrafish
Fruitfly Drosophila melanogaster
Gametogenesis (Germ cell specification and maturation)
• Germ line specification (g.l. stem cells first)
• Germ line migration to the gonads
• Meiosis
• Gamete maturation
Gametogenesisoogenesis spermatogenesis
After fertilization, the zygote will essentially be an activated egg
Frog oocyte
Table 19.2 Cellular components stored in the mature oocyte of Xenopus Laevis
ComponentApproximate excess over amount in larval cells
Mitochondria100,000
RNA polymerases60,000 - 100,000
DNA polymerases100,000
Ribosomes200,000
tRNA10,000
Histones15,000
Deoxyribonucleoside triphosphates2,500Note Yolk –vitellegenin –from liver
Laskey 1979
Table 19.2 Cellular components stored in the mature oocyte of Xenopus Laevis
ComponentApproximate excess over amount in larval cells
Mitochondria100,000
RNA polymerases60,000 - 100,000
DNA polymerases100,000
Ribosomes200,000
tRNA10,000
Histones15,000
Deoxyribonucleoside triphosphates2,500Yolk –vitellegenin FROM LIVER
Laskey 1979 2 .Micro-pinocytosis – vesicle delivery from other cells
1 .Oocytes’ massive bio-synthesis of macromolecules
Fruitfly Drosophila melanogaster
Gametogenesis/Fertilization Unit
OPPORTUNITY TO FOCUS ON MICROTUBULES
Microtubles in mitosis/meiosis
Movie1Life of cell 2
http://biolog-e.ls.biu.ac.il/faculty/wides/80-557/movies/MCB1803ActinMyosin.MOV
Kinesins towards+ Dyenins towards-
http://www.youtube.com/watch?v=4TGDPotbJV4Kinesin walk
Attachment later by vegetal Cortex microfilaments
Transport viaMicrotubules-Assymetric placementof cytoplasmiccomponents (RNA)
Microtubles in oogenesis, creating assymetry in cytoplasm
Figure 2.1 Developmental History of the Leopard Frog, Rana pipiens
Gametogenesisspermatogenesis
oogenesis
First: Microtubles and the flagellum
9+2 micorotuble arrangement - in motile cilia -including most metazoans’ sperm flagella
9 dimer microtubules
+2 monomer microtubules
- primary cilia ineukaryotic cells:
9 :stationary- secondary cilia,
including flagella:9+2 :movement Can see: http://www.youtube.com/watch?v=n40VTfWvh1Y
http://www.youtube.com/watch?v=vQ3CdSiVzUkcilia
Flagellum structure:Sperm and most eukaryotic
flagella
http://www.youtube.com/watch?v=5rqbmLiSkpk
Centriole-> flagellumAcrosomeMitochondria to axonemeCytoplasm
Figure 6 By-the-way: Flagella in Eubacteria,) and in Archea ,(are Analogous,
NOT homologous
Fertilization
Figure 2.21 Major Evolutionary Divergences in Extant Animals
Attraction of sea urchin sperm to egg in Sea water:
Swimming along the gradient of the RESACT peptide
Gametogenesis
and Fertilization Unit
Opportunity: Microtubules and motors
1. Calcium mediated Membrane fusions (3)
Cell-Cell interaction – First example2. Extracellular matrix (ECM) introduction
Vade Mecum Sea Urchin Fertilization
_Zona Pellucida
Ovum
Cumulus