Question

Identify the point where the described mutation is disrupting the production of a normal protein.

( This is all the information provided by the instructor)

Description	Step
In Hb Kempsey an impaired globin subunit interaction locks hemoglobin into its high oxygen affinity state.
Thalassemias due to nonfunctional or rapidly degraded mRNAs with nonsense of frameshift mutations.
I-cell disease due to a failure to add a phosphate group to mannose residues of lysosomal enzymes.
Thalassemias due to reduced production of a globin mRNA because of deletions or mutations in splice sites of a globin gene.
Patients with a substitution that changes the signal sequence to AACAAA produced only a minor fraction of correctly polyadenylated beta-globin mRNA.

Answer 1

ANSWER :- The point that describes the mutations is disrupting the production of normal protein is

:- patients with a substitution that changes the signal sequence to AACAAA produced only a minor fraction of correctly polyadenylated beta-globin mRNA.

The above given points tells the mutation in heamogloin causing thalassemia. The HB is made up of two polypeptide chains, called alpha chain and beta chain. Mutation in alpha chain cause alpha thalassemia and mutation in beta chain cause beta thalassemia. The beta thalassemia is caused by the mutation that disrupt the normal splicing of beta-globin gene to cause beta thalassemia. The defects are found in capping and tailing of beta globulin mRNA. Several beta thalassemia mutation are found during the post translation modification of mRNAs.

We known that the 3' end of mRNA having the untranslated regions, with a polyA tail . If this sequence is not added, the mRNA is unstable. Polyadenylated of MRNA requires enzymatic cleavage of the mRNA, which occurs in response to a signal for the cleavage site, AAUAAA, this is found near the 3'end of most eukaryotic mRNAs. Patients with a substitution that changes the signal sequence to AACAAA produced only a minor fraction of correctly polyadenylated beta globin mRNA.