How does the CFTR protein in cystic fibrosis defect cause an imbalance of Cl- and Na+ ions?
Cystic fibrosis:
· Cystic fibrosis is genetic disorder (autosomal recessive), due to mutation in CFTR (Cystic fibrosis transmembrane conductance regulator) gene.
· CFTR functions as ATP-responsive chloride channel.
· Due to mutation in CFTR gene, the biosynthesis of CFTR protein is altered, the protein thus synthesized may be retained in the endoplasmic reticulum and not transported to the cell surface (apical epithelia).
· Also if the protein reaches the surface, it may not fold properly to function as channel protein.
· Thus, mutation affects transport of negatively charged (anion channel) Chloride ions.
· Choloride transport in turn regulates the movement of water molecules in the cells (especially functioning in lungs and pancreatic cells, which alter the mucous consistency, or inflammation of pancreas).
· The mutation also affects sodium transport in epithelial layers.
· Damages occurring in lungs lead to arterial hypoxia, which alters oxygen affinity of hemoglobin.
How does the CFTR protein in cystic fibrosis defect cause an imbalance of Cl- and Na+...
What is cystic fibrosis? Which amino acid is missing in the CFTR protein in people with cystic fibrosis? What is the function of a normal CFTR protein? What is the malfunction in a CFTR protein in people with cystic fibrosis?
1. Describe the genetic defect in cystic fibrosis 2. How does the underlying genetic defect in cystic fibrosis lead to pulmonary and exocrine gland dysfunction?
How does an imbalance of Cl- and Na+ ions affect the flow of water by osmosis into the lumen from the extracellular space?
Mutations in the CFTR gene result in cystic fibrosis in humans, a condition in which abnormal secretions are present in the lungs, pancreas, and sweat glands. In the effort to positionally clone the CFTR gene, the gene was mapped to a region of 500 kb on chromosome 7 containing three candidate genes. Using your knowledge of the disease symptoms, how would you distinguish between the candidate genes to decide which is most likely to encode the CFTR gene?
Question 26 (4 points) Bonus question: The CFTR protein is found in the plasma membrane of individuals unaffected with cystic fibrosis. A common mutation in CFTR causes the protein to be trapped in the ER and eventually degraded. Why does this happen?
Consider the most common Cystic Fibrosis variant: Wild-type CFTR DNA (Coding-strand): 3 ATC ATC TTT GGT GTT atc att ggt gtt... Cystic Fibrosis odi 1. Add the 5' and 3' designations to the DNA. 2. Write the template sequence for the DNA 3. Transcribe the wild-type and CF DNA into mRNA. Be sure to include the 5'/3' labels. 4. Translate the wild-type and CF mRNA into protein. Be sure to label these ends also. 5. In the above wild-type protein,...
A 14-year-old girl with cystic fibrosis has complained of an increased cough productive of green sputum over the last week. She also complained of being increasingly short of breath, and she is noticeably wheezing on physical examination. Arterial blood was drawn and sampled, revealing the following values: pCO2 50 mm Hg pO2 55 mm Hg Hemoglobin - O2 saturation 45 % [HCO3-] 24 mmol/L 1. Calculate the pH from the values given. 2. How would you classify this girl's primary...
Arterial blood gas case study 1 A 14-year-old girl with cystic fibrosis has complained of an increased cough productive of green sputum over the last week. She also complained of being increasingly short of breath, and she is noticeably wheezing on physical examination. Arterial blood was drawn and sampled, revealing the following values: pH 7.30 pCO2 50 mm Hg pO2 55 mm Hg Hemoglobin - O2 saturation 45 % [HCO3-] 24 meq / liter Questions: 1....
An expectant father is heterozygous (cc) for the mutation known to cause cystic fibrosis. He is confident his children won't have this disease because the mother of his child is confirmed to be homozygous dominant (CC). Under Mendelian rules, their child should be healthy with genotypes of either be CC or Cc. They are quite surprised to learn their child is born with cystic fibrosis. The baby is karyotyped and confirmed to be a euploid (46 chromosomes and no chromosomal...
If the CFTR doesn't work correctly due to a mutation, Cl^- movement is blocked and an abnormally thick sticky mucus is produced on the outside of the cell. This mucus clogs the airways in the lungs, and increases the risk of infection by bacteria. Figure 2 illustrates a mutant CFTR channel in the epithelial cells lining the lung. Suppose the Na^+ channel in the figure was open. Why would more Na^+ enter a cell with mutant CFTR than a cell...