Influenza genetics case study Influenza is a highly contagious virus caused by a
ID: 273985 • Letter: I
Question
Influenza genetics case study Influenza is a highly contagious virus caused by an RNA-virus, meaning that it is comprised primarily of RNA instead of DNA as its genetic material. Its genome is 14,000 nucleotides on eight pieces of RNA and can only code for 11 proteins. The most heavily studied influenza protein is hemagglutinin (HA) protein. This protein helps the fu virus infect cells, thus the structure of this protein can vary in different viral strains. You are serving as a research assistant in a flu lab and are trying to discern why the vaccine was ineffective this year. You know the predicted sequence for the HA mRNA and were given 4 additional sequences from labs around the world to compare. Follow the instructions for each strain and determine which is the most likely variant causing the flu this year. Typical HA RNA 5' UAACCAUCAAG strain #1 RNA 5URACCAUGAAuguyGCyUUGAGQUAGAUUC 3 1. Using the same reading frame: Identify the nucleotide change that has occurred and the codon that will be affected. Determine what, if any, change has occurred to the protein that is produced as a result of this nucleotide change. What type of mutation is this? a. b. c.Explanation / Answer
1) UA ACC AUG AAG ACU AUC AUU GCU UUG AGC UAC AUU C
T M K T I I A L S Y I
NUCLEOTIDE CHANGE
UA ACC AUG AGG ACU AUC AUU GCU UUG AGC UAC AUU C
PROTEIN CHANGE (missense mtation)
T M R T I I A L S Y I
2) UA ACC AUG AAG ACU AUC AUU GCU UUG AGC UAC AUU C
T M K T I I A L S Y I
NUCLEOTIDE CHANGE
UA ACC AUG AAG ACU AUC AUU GCU UAG AGC UAC AUU C
PROTEIN CHANGE (nonsense mtation)
T M K T I I A @
3) UA ACC AUG AAG ACU AUC AUU GCU UUG AGC UAC AUU C
T M K T I I A L S Y I
NUCLEOTIDE CHANGE
UA ACC AUG AAG ACC AUC AUU GCU UUG AGC UAC AUU C
PROTEIN CHANGE (silent mtation)
T M K T I I A L S Y I
4) UA ACC AUG AAG ACU AUC AUU GCU UUG AGC UAC AUU C
T M K T I I A L S Y I
NUCLEOTIDE CHANGE
UA ACC AUG AAG ACA UCA UUG CUU UGA GCU ACA UUC
PROTEIN CHANGE ( FRAMESHIFT- deletion mtation)
T M K T S L L @
from all 4 strain, strain 1 will cause the new flu. apart from 1, strain 2,3 and 4 have nonsense, silent and frameshift deletion which either have no effect on protein or prematurely terminate the protein.