The human TP53 gene encodes a cellular protein of 393 amino acids in length that corresponds to 393 codons in the mRNA coding sequence.

The human TP53 gene encodes a cellular protein of 393 amino acids in length that corresponds to 393 codons in the mRNA coding sequence. mRNA sequence analysis was performed and mutations were identified (that originated from the DNA sequence) in tumours from three different individuals when compared to their normal somatic cell mRNA sequence.

A. Use the RNA codon chart provided in Figure 2, for each of the mutations (i) to (iii) below. Identify any changes in the amino acid sequence of the mutant protein and any potential consequence/s of the mutation for the TP53 protein considering the mutation’s codon position.

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Gly Phe Leu Glu Ser A Asp U A A C G G C G U G Tyr UC A Stop AJA UC G Stop GA U C A CU A G Cys U G C

A C Val A Stop C G U U G A G Tre U UC G Arg A G A C U A Leu C, U A C G Sar U C GA C U G A A G Lys CU

UC Pro G A U U AG Asn C U A HIS G/A C G C Thr GIn Arg Met Start

Figure 2 RNA codon chart.

i.Individual 1: A point mutation of GCG (codon 21) mutated to GCU.

(1 mark)

ii.Individual 2: A point mutation with UAC (codon 200) mutated to UAG.

(2 marks)

iii.Individual 3: And insertion mutation with UUA CGC AAG GUC AGC (codons 6-10) mutated to UUA CGC GAA GGU CAG C.

(3 marks)

B .The tumour suppressor gene TP53 and its encoded TP53 protein is associated with one of the hallmarks of cancer, resisting cell death. Briefly describe (in no more than 150 words) the effect that a mutation in TP53, such as the one found in Individual 3, could play in contributing to a cancer acquiring resistance to cell death. Include a word count in your answer.

(4 marks)