1. MECP2 is a protein that binds specific regions of the genome and packages the
ID: 91561 • Letter: 1
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1. MECP2 is a protein that binds specific regions of the genome and packages the DNA into heterochromatin. MECP2 is highly expressed in the brain, and reduction of MECP2 function is linked to neurodevelopment disorders, including Retts syndrome and autism. Researchers found different point mutations in the 3 UTR of the MECP2 gene in four patients with autism. They hypothesized that the mutated sequences regulate MECP2 mRNA stability. To test their hypothesis, they created a luciferase reporter gene vector, which they plan to transfect into a neuronal cell line They carry out the reporter assay with the following sequences inserted into the vector and measure luciferase enzyme activity Insert sequence Units of luciferase activity 390 5 1) No insert (standard 3' UTR) 410 6 2) WT MECP2 3'UTR 55 4 3) MECP2 3' UTR w/ nt1832 G-SC 385 9 4) MECP2 3' UTR w/ nt2015 G->A. 210 +/-5 5) MECP2 3' UTR w/ nt4017 T->A 6) MECP2 3' UTR w/ nt4417 G->A 315 3Explanation / Answer
Answer. MECP2 gene expression is related with point mutation in 3’- UTR region of the gene. Where there was no insert in the luciferase vector, the relative luciferase activity was 390 with standard deviation of 5. The WT (wild type) did not affect plasmid expression and slightly enhanced it with relative unit of 410 with standard deviation of 6. When MECP2 gene with point mutation (G>C) at 1832 nucleotide position with G to A substitution was inserted, there was significant decrease in gene expression (55 RLU with std. deviation of 4). Point mutation at 2015 and 4417 base with G to A substitution had slight decrease in gene expression. Nucleotide substitution at 4017 base pair with T to A substitution had moderate decrease in gene expression. From the result it is clear that G to C point mutation at 1832 nucleotide position has more detrimental effect on MECP2 gene expression followed by T to A substitution at 4017 nucleotide position.
Luciferase vector
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