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Questions and Answers
What is a primary characteristic of iPS cells?
What is a primary characteristic of iPS cells?
Which of the following factors is NOT one of the original four Yamanaka factors used for reprogramming cells?
Which of the following factors is NOT one of the original four Yamanaka factors used for reprogramming cells?
What is a potential application of iPS cells in disease modeling?
What is a potential application of iPS cells in disease modeling?
What is the significance of patient-donor specific iPS cells?
What is the significance of patient-donor specific iPS cells?
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Which statement correctly describes the transition between different cell states during development?
Which statement correctly describes the transition between different cell states during development?
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What advantage do iPS cells have over traditional stem cell sources?
What advantage do iPS cells have over traditional stem cell sources?
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What is a common reprogramming method for converting differentiated cells into iPS cells?
What is a common reprogramming method for converting differentiated cells into iPS cells?
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What primarily influences the differentiation ability of different iPSC lines?
What primarily influences the differentiation ability of different iPSC lines?
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What is a defining characteristic of embryonic stem cells (ESCs)?
What is a defining characteristic of embryonic stem cells (ESCs)?
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How do epiblast-derived stem cells (EpiSCs) differ from embryonic stem cells (ESCs) in terms of pluripotency?
How do epiblast-derived stem cells (EpiSCs) differ from embryonic stem cells (ESCs) in terms of pluripotency?
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Which statement about the differentiation responsiveness of EpiSCs is true?
Which statement about the differentiation responsiveness of EpiSCs is true?
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What effect do epigenetic memories have on iPSCs?
What effect do epigenetic memories have on iPSCs?
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What is the primary role of Oct-3/4 in the context of pluripotent stem cells?
What is the primary role of Oct-3/4 in the context of pluripotent stem cells?
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Which histone modification is typically associated with active transcription?
Which histone modification is typically associated with active transcription?
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During the early phase of reprogramming into iPS cells, which of the following events occurs?
During the early phase of reprogramming into iPS cells, which of the following events occurs?
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What is the effect of DNA methylation in the context of gene expression?
What is the effect of DNA methylation in the context of gene expression?
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Which of the following factors is NOT associated with the maintenance of pluripotency?
Which of the following factors is NOT associated with the maintenance of pluripotency?
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What is a key change occurring during the late phase of reprogramming?
What is a key change occurring during the late phase of reprogramming?
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Which histone modification is associated with gene repression?
Which histone modification is associated with gene repression?
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Which process must occur to ensure successful reprogramming of a somatic cell into an iPS cell?
Which process must occur to ensure successful reprogramming of a somatic cell into an iPS cell?
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In which types of organisms has reprogramming to iPS cells been shown to be universal?
In which types of organisms has reprogramming to iPS cells been shown to be universal?
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What happens to Oct4 and Nanog during the transition from differentiated cells to ES or iPS cells?
What happens to Oct4 and Nanog during the transition from differentiated cells to ES or iPS cells?
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What is the primary role of epigenetic modifications in gene expression?
What is the primary role of epigenetic modifications in gene expression?
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How does DNA methylation affect gene expression?
How does DNA methylation affect gene expression?
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Which factor is critical for maintaining pluripotency in stem cells?
Which factor is critical for maintaining pluripotency in stem cells?
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What is the process by which chromatin becomes more accessible for transcription called?
What is the process by which chromatin becomes more accessible for transcription called?
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What is one of the primary functions of transcription factors in relation to the genome?
What is one of the primary functions of transcription factors in relation to the genome?
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What characterizes the stochastic phase of reprogramming?
What characterizes the stochastic phase of reprogramming?
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Which of the following statements about histone modifications is true?
Which of the following statements about histone modifications is true?
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What is a defining feature of the deterministic phase in iPSC reprogramming?
What is a defining feature of the deterministic phase in iPSC reprogramming?
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What characterizes epigenetic regulation of gene expression?
What characterizes epigenetic regulation of gene expression?
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Which method is considered the 'gold standard' for assessing iPSC pluripotency?
Which method is considered the 'gold standard' for assessing iPSC pluripotency?
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What role do transcription factors play in chromatin structural regulation?
What role do transcription factors play in chromatin structural regulation?
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What does the bivalent methylation of H3K4m33/H3K27me3 indicate during reprogramming?
What does the bivalent methylation of H3K4m33/H3K27me3 indicate during reprogramming?
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What does the phrase 'Genetics proposes, epigenetics disposes' imply?
What does the phrase 'Genetics proposes, epigenetics disposes' imply?
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Which of the following is NOT typically assessed when determining iPSC pluripotency?
Which of the following is NOT typically assessed when determining iPSC pluripotency?
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During reprogramming, what shift occurs alongside cellular proliferation?
During reprogramming, what shift occurs alongside cellular proliferation?
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What is a primary characteristic of the mesenchymal-epithelial transition in iPSCs?
What is a primary characteristic of the mesenchymal-epithelial transition in iPSCs?
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Which conclusion can be drawn from the generation of teratomas by iPSCs?
Which conclusion can be drawn from the generation of teratomas by iPSCs?
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In which phase of reprogramming do lineage specific genes undergo down-regulation?
In which phase of reprogramming do lineage specific genes undergo down-regulation?
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What morphological change is associated with the progression to a stable pluripotent state?
What morphological change is associated with the progression to a stable pluripotent state?
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Study Notes
Lecture 3: iPS Cells
- Induced pluripotent stem cells (iPS cells) are adult cells reprogrammed back into a pluripotent state.
- iPS cells are exciting because they are self-renewing and can differentiate into any cell type in the adult body.
- A scalable supply of iPS cells is possible, eliminating the need for donor human embryos.
- iPS cells are relatively easy to generate from donor tissue in a lab.
- Patient-specific iPS cells can be used for in vitro disease models.
- iPS cells have potential in drug, anti-cancer discoveries, and clinical cell-based therapies.
- iPS cells hold significant promise for the future.
Key Factors for Reprogramming
- Four key factors, OCT3/4, SOX2, KLF4, and c-MYC (OSKM), can be used to reprogram adult fibroblasts into pluripotent cells.
- These factors were identified in the experiments conducted by Yamanaka and colleagues.
- Many other reprogramming methods have been attempted/tested.
Different Reprogramming Methods
- Various methods exist for delivering reprogramming factors, each with unique efficiency and safety profiles.
- These methods include retro/lentiviruses, lentiviruses, excisable lentiviruses, adenoviruses, RNA, transposons, episomal vectors, small molecules, and proteins.
Molecular Events Underlying Reprogramming
- The process of cellular differentiation involves epigenetic modifications, such as DNA methylation and histone modifications, regulating gene expression.
- These modifications control the access of transcription factors to DNA and rearrange chromatin structure which determines cell type characteristics and functions.
- Oct3/4 is a regulatory transcription factor that is crucial to sustaining pluripotent cells.
- Modifications like histone acetylation (Ac-H3) and DNA methylation are involved in regulating gene expression during reprogramming.
Assessing iPS Cell Pluripotency
- iPSCs are assessed for pluripotency through various methods, including teratoma formation, transcriptome analysis, and chimera formation.
- These methods assess a cell's potential to differentiate into various cell types.
Types of Pluripotent Stem Cells (PSCs)
- Embryonic stem cells (ESCs) and epiblast-derived stem cells (EpiSCs) are two types of PSCs.
- ESCs are derived from pre-implantation blastocysts.
- EpiSCs are derived from the epiblast of the post-implantation embryo.
- Differences in their behaviours relate to their different pluripotent states.
Methods for differentiating iPSCs
- iPSCs can be differentiated into various cell types using different culture approaches, including 2-Dimensional and embryoid bodies.
- Removal of pluripotency support (like LIF) allows for directed differentiation.
- Cell-cell aggregation or random association of cells supports differentiation.
- Culture approaches mimic conditions in the embryo.
Safety Considerations for Clinical Use
- Careful assessment of the reprogramming process, identification of incompletely differentiated cells, and characterization of genomic and epigenetic changes during culture are essential in clinical translation.
- Development of standard operating procedures (SOPs) for clinical-grade iPSCs is crucial for safety.
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Description
This quiz covers the concept of induced pluripotent stem cells (iPS cells), their generation, and key factors involved in their reprogramming. It also explores various methods for generating iPS cells and their potential applications in medicine and research. Test your knowledge on iPS cells and their transformative role in biotechnology.
