FinalWalk
Dec10-10, 05:21 AM
ABC Syndrome is a genetic disorder clinically characterized by the appearance of numerous non-cancerous tumors in many organs but particularly in the brain, skin, heart and skeletal muscle. The syndrome is rare affecting only 1 in 6000 individuals and is generally diagnosed after the age of 40 when the tumors become large and obvious. Concurrent with the appearance of the tumors, individuals with this disorder generally display epilepsy, dementia or a combination of both. Patients with ABC syndrome show a range in severity of symptoms. Some have many tumors as well as epilepsy and dementia while others display very few tumors and lead a fairly normal life. The normal protein that is absent or defective in patients is called ABC protein and the gene coding for ABC protein is called the ABC gene.
The first complete cDNA clone coding for normal human ABC protein was isolated from a human cDNA library. Since some amino acid sequence data of the ABC protein was available, a degenerate probe was used to screen the library. (Please note - antibodies were not and are now not available for the ABC protein). Following that feat, a genomic clone that codes for the normal ABC gene was isolated. Quite a number of different mutations in the ABC gene of patients with the disorder have been characterized and include base substitutions that result in missence and nonsense codons as well as deletions and insertions that result in frame shifts. Complete nucleotide sequence information of both the human cDNA and human genomic clone has been obtained. The ABC protein is a single polypeptide chain composed of 1164 amino acids.
I have two questions about this that are throwing me off about this disorder, therest I understand.
Q1: In light of the information provided in the text above, how might the scientists have isolated the ABC human genomic clone? Give a brief experimental design.
Q2: Design a screen for the mutation present in patient described above to determine whether offspring of this individual will be affected with ABC Syndrome using PCR in your methodology.
The first complete cDNA clone coding for normal human ABC protein was isolated from a human cDNA library. Since some amino acid sequence data of the ABC protein was available, a degenerate probe was used to screen the library. (Please note - antibodies were not and are now not available for the ABC protein). Following that feat, a genomic clone that codes for the normal ABC gene was isolated. Quite a number of different mutations in the ABC gene of patients with the disorder have been characterized and include base substitutions that result in missence and nonsense codons as well as deletions and insertions that result in frame shifts. Complete nucleotide sequence information of both the human cDNA and human genomic clone has been obtained. The ABC protein is a single polypeptide chain composed of 1164 amino acids.
I have two questions about this that are throwing me off about this disorder, therest I understand.
Q1: In light of the information provided in the text above, how might the scientists have isolated the ABC human genomic clone? Give a brief experimental design.
Q2: Design a screen for the mutation present in patient described above to determine whether offspring of this individual will be affected with ABC Syndrome using PCR in your methodology.