Committed to terminal differentiation transformation

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Unformatted text preview: de without limit After division stem cells can » Remain stem cells (“Stemness” genes) » (or) Become committed to terminal differentiation Transformation Transformation Stem Cells Normal stem cell division 2 daughter cells will result 1. Daughter stem cell (remains a stem cell) does not Daughter differentiate differentiate 2. Committed stem cell - terminally differentiate Transformation Transformation Stem Cells Transformation Transformation Stem Cells Stem cell - rapid cell division – Will not by itself produce an imbalance between cell Will production and cell destruction (cancer) Transformation Transformation Stem Cells Two possible mechanisms in differentiation could Two lead tumor growth lead 1. 2. 2. » Daughter cells are committed but retain ability to continue Daughter on indefinitely - can’t be discarded at the end of the process on Transformation Transformation Immortalized Cells Definition – Normal life cycle of cells – After 50 to 60 doublings (divisions) cells stop growth » “Senescent” - – Senescence regulated by “growth-inhibitory proteins” » Retinoblasoma (RB) » p53 gene Transformation Transformation Immortalized Cells Mutations in either RB or p53 genes – Cells continue to divide beyond normal limits – These cells eventually reach “crisis” stage » Will die in vast numbers – Some cells by pass “crisis” and become immortalized Some continue to proliferate continue Some immortalized cells have been in culture for Some decades decades Transformation Transformation Mechanisms of Senescence and Crisis In Normal Cells Telomeres – Count number of replicative generations cells go Count through (like a timer) through – After a specific number of cell d...
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This note was uploaded on 04/18/2013 for the course BIO 205 taught by Professor Dr.cady during the Spring '11 term at Bradley.

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