Developmental gene regulation Flashcards
How are genes selectively expressed?
Differential gene expression
Cellular differentiation
Epigenetics
What is meiosis?
Formation of haploid spermatocyte or oocyte
Two successive rounds of cell division without S phase
What is chromosome crossover and when does it occur?
Homologous chromosomes pair up and can switch to its pair by a chiasma
Occurs during meiosis at prophase I
When does gene expression begin?
During gastrulation
What are four cell activities during development?
Proliferation
Specialization
Interactions
Movements
How do cells communicate?
Intercellular and intracellular signals
How do cells differentiate?
Different environments
Signals from neighboring cells and cells outside the group
What is a totipotent stem cell?
Cells from fusion of egg and sperm
Can differentiate into whole organism and placenta
What are pluripotent stem cells?
Cannot develop into whole organism if implanted
Cannot develop into placenta
What are multipotent stem cells?
Can differentiate into few related cells
Adult stem cells
What is stem cell differentiation and how is it controlled?
Into terminally different cells that generally die, or can remain permanent
Controlled by telomeres. Telomerase expressed in stem cells is generally turned off in the differentiated cells.
What are embryonic stem cells?
Pluripotent - isolated from blastocyst
TFs suppress gene expression
What are adult stem cells?
Multipotent - limited ability to differentiate to other cells
In almost all body tissues
Used in therapies
What is cellular differentiation?
Specialization of cells
Most cells stop dividing to differentiate
What is selective expression of genes in cells?
Highly regulated
Differential expression
Tissue specific - epigenetics
What causes tissue specific expression?
Changes in chromatin organization, histone modification, and DNA methylation
How does intercellular signaling relate to cell differentiation?
Signals from neighboring cells and cells outside of group
Changes in DNA transcription
What are master transcription regulators and how do they function?
Selectively turn on genes needed and suppress others to change identity of cells during development
Govern development of specialized cells in tissues
Express tissue specific genes
What are examples of master transcription factors?
Twist1 for mesoderm
MyoD in muscles
Mist1 in pancreas
SOX10 in myelination
What are the HOX complexes and how do they function?
HoxA, HoxB, HoxC, HoxD
Gene family that controls segmenting in body. Code for TFs.
Morphogens
What are morphogens?
Specify position of cells in early embryo
What is epigenetics?
Change gene expression for different tissues
Same genes expressed in same cells of each tissue
What is epigenetic inheritance?
Inheritance of phenotypic changes that do not result from changes in nucleotide sequence of DNA
What can cause epigenetic inheritance?
Modification in chromatin
DNA methylation
Histone modificiations
When do epigenetic changes occur?
During differentiation
