Transcript Answers to Quiz 7 BIol203 Fall 2013ppt

The Arristaless-like (Arl) gene below carries a homeodomain DNA binding domain (HD). Quiz 7: Biol 203 Fall 2013
Furthermore, it has a proven activator domain (A) and repressor domain (R).
Name:_______________
cDNAs with A-R-HD reveal no function, however, cDNAs with A-HD have activator like
Lab:_______________
properties and R-HD have repressor like properties. No cDNAs are found with HD alone.
A loss of function mutation for this gene in the HD is has no toes in homozygous (homo) animals.
WT animals have 5 toes, whereas heterozygous (het) loss of function animals have 4 toes.
You have identified several heterozygous mice that have 6 or more toes and you have identified a SNP
that creates a BamHI site in the gene, which correlates with the phenotype.
24pts
Arl
A
R
HD
10Kb EcoR1 fragment
EcoR1
EcoR1
Coding exon 1 contributes 100 amino acids (10Kd) to the protein, exon 2 contributes 5Kd,
exon 3 contributes 20Kd and exon 4 contributes 30Kd to the protein.
Q1(12pts).
What are the molecular weights (MWs) of the proteins derived from the WT gene?_3pts.__45kd, 60kd, 65kd_
Where would the SNP likely be in the gene?_2pt._ SNP in either intron or exon: Needs to affect A or R protein or splicing (not HD).
What will this SNP mutation do to the eventual mRNA and/or protein?_2pt._stop codon, amino acid shift, makes a mistake in splicing
but they CANNOT say that it will create a null mutation or a loss of function mutation.
Based on how you defined the SNP, what are the MWs of proteins produced in homo SNP animals?
2pts. one of the three proteins specified in answer 1 will be lost, unless it is a missense mutation
What does Arl do in the toe forming pathway?
3pts they have to say that it promotes toe formation or inhibits a protein that normally makes toes
Q2(12pts).
Using RFLP analysis, describe what would be seen using the HD portion of the coding sequence
as a radioactive hybridization probe after Southern blotting of digested genomic DNA for
homozygous, heterozygous animals containing the SNP and WT animals.
Please make sure to label your digests and genotypes for each lane of your blot,
as well as the sizes of fragments produced after hybridization.