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.
Animal cell undergoes simillar early embryonic development • From Egg To Tadpole next • Blastula next • Gastrulation next • Huamn embryo development next
A cell can be determined long before it show any obervious outwad sign of differentiation • Gastrula Endoderm,Mesoderm,Ectodermnext • Embryo Transplation next • Misplaced tissuenext
How do two cells with the same genome come to be different? • Sister cells can be born different by an asymmetric cell division next • Cell-to-cell interaction in cell fate determination next • Embryonic Induction 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 RemainTotipotent • 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 factorsThese 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.next • Differentiated cell can undergo dedifferentiation or transdifferentiation. • Cancer cell can be induce to differentiate.next
Stem Cell • WHAT ARE THE UNIQUE PROPERTIES OF ALL STEM CELLS? next • WHAT ARE EMBRYONIC STEM CELLS? next • WHAT ARE ADULT STEM CELLS? ext • OBSTACLES THAT MUST BE OVERCOME 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. next
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
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.