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41 Cards in this Set
- Front
- Back
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during development, differentiaion of cells involves:
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the turning off and on of genes
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what does the following describe:
differentiation occurs as a result of expression of only a subset of the total genes present in a cell |
Theory of Differential Gene Expression
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how do cells activate only a certain set of genes (inactivating all other genes), and how do they know which set of genes to activate?
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the set of genes activated in a cell is dependent on the set of transcription factors found in the cell
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master control gene
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the first gene in a hierarchy that leads to expression of transcription factors that set into motion a cascade of gene expression
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the master control gene codes for a ...
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transcription factor
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what is the MyoD gene family:
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The master control gene for muscle development
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what is induction:
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when one cell sends a signal to another cell, telling it to differentiate a certain way
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How are master control genes regulated:
1. 2. |
1. induction
2. autonomous regulation |
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what is autonomous regulation:
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cell inherits a “determinant” that causes it to differentiate along a particular path
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what is the suspected “determinant” in autonomous regulation
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mRNA from egg cell that encodes master control gene products
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how do we get multiple cellular phenotypes:
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differential expression and genes and co-expression of regulatory gene products (transcription factors)
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at least ...% of genes in the human genome have functions that are specifically concerned with development and some are ... and have overlapping functions
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1-2
redundant |
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what are the 3 transcription factor protein families involved in development discussed in class:
1. 2. 3. |
1. HOX/homeodomain proteins
2. PAX proteins 3. Zinc finger proteins |
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what kind of proteins do HOX genes encode for:
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homeodomain proteins
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what are homeodomain proteins:
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major regulatory transcription factors in embryogenesis
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1. what do HOX genes do:
2. and what is special about their position in the gene: |
1. Hox genes determine where limbs and other body segments will grow in a developing fetus.
2. there is a direct linear correlation between position of the gene and its temporal and spatial expression |
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what does HOXD13 mutation cause:
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Synpolydactyly (fingers are fused into one large digit and get additional didgit) - between 3rd and 4th fingers and the 4th and 5th toes
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what does HOXA13 mutation cause:
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hand-foot-genital syndrome: shortening of the 1st and 5th digit, hypospadias in males and bicornuate uterus in females
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what is hypospadias:
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abnormally placed urinary meatus (opening)
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Paired-Box (PAX) Genes are important for development of:
1. 2. 3. |
1. nervous system
2. vertebral column 3. eyes |
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Klein-Waardenburg Syndrome is caused by a mutation in:
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PAX3
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what are the manisfestations of Klein-Waardenburg Syndrome:
1. 2. 3. 4. |
1. dystopia canthorum (eyes wide apart)
2. pigmentary abnormalities (frontal white blaze of hair, patchy hypopigmentation of skin, iris heterochromia) 3. congenital deafness 4. limb abnormalities |
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aniridia may be due to mutation in ... and is characterized by ... and is the key feature in ... syndrome
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PAX6
absence of the iris WAGR |
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... are transcription factors in which DNA-binding domain contains finger-like loops with Cys and/or His forming a complex with Zn
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Zinc Finger Genes
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what genes control various developmental processes, such as kidney and brain development
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Zinc Finger Genes
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incomplete cleavage of the developing brain into separate hemispheres and ventricles
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Holoprosencephaly
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Holoprosencephaly is caused by mutation in ...
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ZIC2 or sonic hedgehog protein
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Greig Cephalopolysyndactyly is caused by a mutation in ...
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GLI3
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Greig Cephalopolysyndactyly causes what kind of abnormalities
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head, hand, and foot abnormalities
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Transforming Growth Factor (TGF)-β is important in
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1. organogenesis
2. induction and patterning of mesoderm 3. skeletal development |
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what are 2 examples of (TGF)-β:
1. 2. |
1. Nodal - mesoderm induction
2. BMP (bone morphogenetic protein) |
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... is responsible for anteroposterior patterning, regionalization of brain, limb outgrowth
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Fibroblast Growth Factor (FGF)
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mutaions in Fibroblast Growth Factor (FGF) do not usually occur in the genes that encode the protein but in the genes that encode the ...
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receptor
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Apert Syndrome is caused by mutation in ... and causes:
1. 2. |
FGF receptor (FGFR2)
1. premature fusion of cranial sutures 2. hand and foot abnormalities |
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craniosynostosis is
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premature fusion of one or multiple cranial sutures
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Achondroplasia is:
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most common form of short stature with disproportionately short limbs -- dwarfism with short arms and legs
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what causes Achondroplasia:
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mutation in FGF receptor (FGFR3)
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Sonic Hedgehog (SHH) Protein binds to receptor called ... and is does ... and ...
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patched
notochord and brain development limb outgrowth |
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mutations in PTCH (patched gene) can cause:
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Gorlin syndrome (nevoid basal cell carcinoma syndrome)
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Gorlin Syndrome not only causes congenital malformations, but patients are prone to ...
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cancer
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what does the following describe:
multiple basal cell carcinoma, dental cysts, palmar and plantar pits, bifid, macrocephaly, congenital malformations |
Gorlin syndrome
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