Presentation on theme: "Cell Determination & Cell Differentiation. Overview of birth lineage and death."— Presentation transcript:
Cell Determination & Cell Differentiation
Overview of birth lineage and death
All cells are derived from a singl cell
Cell Determination CELL DETERMINATION is the process by which portions of the genome are selected for expression in different embryonic cells. This involves developmental decisions that gradually restrict cell fate. Cells can progress from TOTIPOTENT to PLURIPOTENT to DETERMINED.
From Egg To Tadpole next next Blastula next next Gastrulation next next Huamn embryo development next next Animal cell undergoes simillar early embryonic development
A cell can be determined long before it show any obervious outwad sign of differentiation Gastrula Endoderm,Mesoderm,Ectodermnextnext Embryo Transplation next next Misplaced tissue nextnext
How do two cells with the same genome come to be different? Sister cells can be born different by an asymmetric cell division next next Cell-to-cell interaction in cell fate determination next next Embryonic Induction next next
Housekeeping gene Housekeeping Gene serving a fuction required in all the cell types of an organism, regardless of their specialized role.
luxury gene Luxury gene Gene performing specialized function in a definite type of cell, not required by all cell types of an organism.
Cell Differentiation Differentiation – The process whereby an unspecialized early embryonic cell acquires the features of a specialized cell such as a heart, liver, or muscle cell.
Differentiated Cell Remain Totipotent Cloning of animal by nulear transfer
Principle of Cell Differentiation Each differentiated cell contains a complete genome. The differences between different types of cells are only duo to expression of different kinds of proteins, that is, a set of genes are switched on in a certain type of cell, meanwhile are switched off in another type of cell.
Cell differentiation is controlled by Transcription Tissue specific transcription factors These proteins cause the experssion of a whole block of proteins that together give cell its identity.
Cell Differentiation is reversible Embryonic Stem cell (ES) can complete the whole process of differentiation in proper environment.nextnext Differentiated cell can undergo dedifferentiation or transdifferentiation. Cancer cell can be induce to differentiate.nextnext
Stem Cell WHAT ARE THE UNIQUE PROPERTIES OF ALL STEM CELLS? nextnext WHAT ARE EMBRYONIC STEM CELLS? next next WHAT ARE ADULT STEM CELLS? extext OBSTACLES THAT MUST BE OVERCOME next next
All stem cells have three general properties Stem cells are capable of dividing and renewing themselves for long periods. Stem cells are unspecialized. Stem cells can give rise to specialized cells. continue
WHAT ARE EMBRYONIC STEM CELLS? Embryonic stem cells – Primitive (undifferentiated) cells from the embryo that have the potential to become a wide variety of specialized cell types. Human embryonic stem cells are derived from blastocyst next
Diseases that might be treated by ES cells Diseases that might be treated by transplanting cells generated from human embryonic stem cells include Parkinson’s disease, diabetes, traumatic spinal cord injury, Purkinje cell degeneration, Duchenne’s muscular dystrophy, heart disease, and vision and hearing loss. nextnext
How are embryonic stem cells stimulated to differentiate?
How are embryonic stem cells stimulated to differentiate? continued
WHAT ARE ADULT STEM CELLS? Adult stem cell–An undifferentiated cell found in a differentiated tissue that can renew itself and (with certain limitations) differentiate to yield all the specialized cell types of the tissue from which it originated. next
Heart muscle repair with adult stem cells.
OBSTACLES THAT MUST BE OVERCOME Proliferate extensively and generate sufficient quantities of tissue. Differentiate into the desired cell type(s). Survive in the recipient after transplant.
OBSTACLES THAT MUST BE OVERCOME continued Integrate into the surrounding tissue after transplant. Function appropriately for the duration of the recipient’s life. Avoid harming the recipient in any way.
The stages of cleavage in Xenopus
Early stages of mouse development
Early mouse embryo
Layers of germ cell
Differetiation of Human Tissue
Embryonic Germ Layers From Which Differentiated Tissues Develop
Development of the Preimplantation Blastocyst in Humans
40 weeks of huamn
Two wing bud
The standard test for cell determination
Clone pig A
Clone Pig B
Clone Pig C
Birth of Dolly
Dolly,1 year old
Dolly with Reportor
Ainstan & Hitler
Dolly and Polly
Dolly,6 years old
Dolly with Wilmut
Two ways making sister cells different
Asymmetric division are particularly common at the beginning of development, when the fertilized egg divides to give daughter cells with different fates,but they also occur at later stages—in the genesis of nerbe cells,for example. next next
Asymmetric division segregating P granules into the founder cel of the C.elegans germ line.
The linegae tree for the cells that form the gut of C.elegans.
The pattern of the cell divisions in the early nematode embryo.
Cell-signal path ways controlling assignment of different characters to the cells in a four-cell nematode embryo.
Vertebrate embryos rely extensively upon inductive interactions to diversify the number of different kinds of cells in the embryo.nextnext
Induction is the process by which one group of cells produces a signal that determines the fate of a second group of cells.
This implies both the capacity to produce a signal (ligand) by the inducing cells and the competence of the responding cells to receive and interpret the signal via a signal transduction pathway. The chemical characterist of inducer is protein.
The presence of organizing centers—the Mangold–Spemann experiment.a
The presence of organizing centers—the Mangold–Spemann experiment.b
Patterning by sequential induction
Development of Human Embryonic Tissues
Techniques for Generating Embryonic Stem Cell Cultures