Lecture 1 exercises
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Contents
DNA
Novice
- Which chromosome is mindbomb1 (Dm) on?
- Search all NCBI databases for mindbomb1
- Find that official symbol is mib1
- In NCBI Gene database for Drosophila melanogaster, we see gene lies on chromosome 3L
- How many SNPs does its human homolog have?
- From NCBI Gene page, click on "Holologs of the mib1 gene
- Arrive at NCBI HomoloGene DB for MIB1, click on Homo Sapiens
- From list of links at right, click on SNP
- Takes you to NCBI dbSNP. We see it lists 1786 for active.
- Could also go straight to dbSNP and type mib1 AND homo sapiens
- How many of them would change the protein translated from it?
- Go to Ensembl and look for mib1 in human
- Click on the Gene result
- At the top, click on the "Gene: MIB1" tab
- In the navigation on the left, click "Variation table" inder Genetic Variation
- If you click on ALL we see that Ensembl lists 81 total variations, and 70 of them are attributed to SNPs
- Brute force: You can also download the variations from dbSNP and write a perl script to go to each variation and see if the polymorphism changes the encoded protein
Advanced
- What is the sequence (10 bp) 500 bp upstream from TTN
- in human?
- in drosophila?
- Obtain unique identifiers (UIs) for all genes associated with FSHD
- Find ENSGs for them
RNA
Novice
- What are the last 10 nt in the human homolog of mindbomb1?
- Search NCBI Nucleotide mib1 and homo spaiens
- Click on "Homo sapiens mindbomb homolog 1 (Drosophila) (MIB1), mRNA"
- At the very bottom they give the nucleotide sequence:
9241 aaatttcatg gcaatatttt ttactaaatt gaaactatag gttttaaaaa taaagacatt 9301 ttagaaaa
- How many exons would you hypothesize the RNA would have if the last amino acid is a lysine?
- Not sure. I see that looking for the MIB1 homosapiens in NCBI Nucleotide that there are 20 exons listed there.
- How does expression of this gene change in CD4+ T-cells in patients with melanoma?
- Would upregulation of mindbomb1 have any effect on the number of mitochondrial ribosomes?
Advanced
- What is the titin isoform with the largest # of exons?
- Find a transcription factor that upregulates the expression of this mRNA
- Find a microRNA that could suppress it (has >= 14/21 matches)
- Find the exons for all mouse 3’UTRs (don’t download them, just show me the first MB)
- Verify your terminal-K hypothesis
Protein
Novice
- How many glutamines are there in the human homolog of mindbomb protein?
- Look up "mib1 and homo sapiens" in NCBI protein
- Copy the protein sequence at the bottom, beside the word "ORIGIN"
- Use the following perl subroutine to identify the number of glutamines (letter q) in the sequence
sub count_qs { my $sequence = shift; my $count = 0; print "length: " . length($sequence). "\n"; for (my $key = 0; $key < length($sequence); $key++) { my $letter = substr ($sequence, $key, 1); #print $letter; if ($letter eq 'q' ) { $count++; } } print $count . "\n"; }
- Answer: 54
- Name a protein that binds (h)MIB1.
- How many ankyrin repeats does (h)MIB1 have?
- By clicking on the "Graphics" link on the NCBI Protein page, we see that there are several areas labelled ANK. In the chart, it looks like there are 9 separable regions with ANK, each labelled 1-9.
- Name another protein with ankyrin repeats.
- According to Ankyrin Repeat wiki article, many proteins have ankyrin repeats, including NOTCH1.
- Which kingdom of life has the most ankyrin repeats?
- According to same article, eukaryotes have the most.
Advanced
- How many aliphatic amino acids does an ankyrin repeat consensus sequence contain?
- What is the pdb identifier of the homologous region to MIB1 on Ank1?
- How many isoforms of Ank1 have this region?
- How many do not?
- Download all predicted proteins in brachiostoma floridiae
- How many domains does the largest isoform of titin have?