10 Stem Cells

cell of the body other than egg or sperm

the transfer of a cell nucleus from a somatic cell into an egg from which the nucleus has been removed

• cells that have the ability to divide for indefinite periods, to self-renew, & to give rise to specialized cells
• are now being used in many clinical trial
• when a stem cell divides into 2 cells, it produces 1 identical cell & 1 cell that will go on to be specialized (committed cell)

• 1. embryonic stem (ES) cells from the inner cell mass of the blastocyst!
• 2. fetal umbilical cord blood*
• 3. adult tissues, including induced pluripotent stem (iPS) cells

unlimited capacity to specialize into any & all cell types or tissues

capable of giving rise to most cells & tissues of an organism

capable of giving rise to several cell types, a subset of the 300 cell types in the body

cells that are committed to differentiate; they are not self-renewing

an organism, colony, or group of organisms (or a colony of cells) derived from a single organism or cell by asexual reproduction, all having identical genetic constitutions

cloning to produce a pregnancy that results in the birth of a baby

cloning to produce embryonic stem cells for treatment of disease, mechanistic studies, or toxicology studies

• how a clone is made
• 1. isolate a mature, unfertilized egg (secondary oocyte arrested in metaphase II)
• 2. remove the nucleus
• 3. replace it with a donor DIPLOID nucleus from some other somatic cell
• 4. grow the egg into an adult

• with iPS cells, you can take ANY somatic cell from any tissue or organ you want & transfect it with 4-6 transcription factors that will ‘reprogram’ the genome of the cell to become the equivalent of an embryonic stem cell
• adult stem cells are restricted to the lineage of the cells they came from (are only multipotent)
• issue: very inefficient - can’t realistically grow tissues
• also in animal studies cancer is widely observed