Flashcards in 13a: Trinucleotide Repeats Deck (29)
One hypothesis on how trinucleotide repeat expansions occur is related to (X) during which process?
X = Backward slippage of DNA Pol
Trinucleotide repeat expansions (increase/decrease/don't change) in size with each successive generation of patients.
The molecular connection between growing number of trinucleotide repeats and increase in severity of disease phenotype.
Often, increase in severity of disease manifests as:
Younger age of onset
T/F: All diseases that arise by mechanism of tri-NT repeat expansion exhibit anticipation.
In Huntington's Disease, where in gene do the tri-NT repeat expansions occur?
The expansion in HD results in (increase/decrease) size of (X) tract in (Y) protein.
X = glutamine
Y = huntingtin
The mutated version of huntingtin protein (breaks down/aggregates).
Most characteristic result/symptom of neuronal degeneration of HD.
Increased involuntary muscle movements
In Fragile X syndrome, where in gene do the tri-NT repeat expansions occur?
Which tri-NT repeat is implicated in Fragile X syndrome? In which gene?
CGG repeat in FMR1 gene
In (X), the tri-NT repeat expansion in the promoter region cause (Y) and silencing of the (Z) gene.
X = Fragile X syndrome
Y = methylation of CpG islands
Z = FMR1
HD is (dominant/recessive) defect with (gain/loss) of function.
Fragile X is (dominant/recessive) defect with (gain/loss) of function.
(Males/females) more vulnerable to Fragile X syndrome.
Males (only 1 X chromosome)
Friedreich's Ataxia involves (X) tri-NT repeat expansion in which region of (Y) gene?
X = GAA
Y = FRDA1 (frataxin)
Key symptoms of Friedreich's Ataxia.
Loss of voluntary movement and enlarged hearts
Myotonic dystrophy is associated with expansion of (X) tri-NT repeat in (Y) region of (Z) gene.
X = CTG
Y = 3' untranslated region (UTR)
Z = DMPK
The 3' UTR begins just (before/after) stop codon.
An expansion in 3' UTR region compromises which characteristic of the (X) molecule?
X = mRNA
Myotonic dystrophy is (dominant/recessive) defect with (gain/loss) of function.
The 5' UTR of gene is also known as:
The promoter region
T/F: It's possible to predict the precise age of onset of HD based on number of CAG repeats.
False - only approximation
Diseases that result from expansions in (X) regions of gene cannot be amplified by PCR because the expansions are too (Y).
X = non-coding;
Y = large
An alternative technique used to detect large-scale tri-NT expansions is (X), where (DNA/mRNA) is processed/analyzed in which ways?
X = Southern blotting
Digested by restriction enzymes and run on a gel
Since in (X) technique the DNA appears as smear on the gel, it's necessary to subsequently use probe that's labeled with (identical/complementary) sequence.
X = southern blotting;
T/F: Southern blotting incapable of detecting methylation status of gene.
To detect methylation status of gene, the (DNA/mRNA) must be digested by enzyme that specifically:
Digests unmethylated regions