The following DNA contains one transcribed region which comprises 2 exons and on
ID: 161627 • Letter: T
Question
The following DNA contains one transcribed region which comprises 2 exons and one 10-nucleotide intron. The transcription start site (cytosine) and branch point (adenine) are lower-case. 5’-CCCTCGAcTCGTAATGGAAAGGTGCGAGTGGGCaCAGGCGCGGGGAAAATGAGACTATTTGTAGCTGACCCTC-3’
Write the template sequence for this transcribed region. Label 5’ and 3’ ends. Write the pre-mRNA sequence. Label 5’ and 3’ ends and circle the intron (which is removed).
Using single letter amino acid abbreviations, translate the mRNA. Label amino- and carboxyl-termini. An insertion mutation adds a cytosine to the template strand between the first two codons.
Translate the new mRNA.
Explanation / Answer
5’-CCCTCGAcTCGTAATGGAAAGGTGCGAGTGGGCaCAGGCGCGGGGAAAATGAGACTATTTGTAGCTGACCCTC-3’
3' GGGAGATgAGCATTACCTTTCCACGCTCACCCGtGTCCGCGCCCCTTTTACTCTGATAAACATCGACTGGGAG-5'
3'-5' is a template strand so pre-mRNA is nothing but the given sequence in the question that is complementary except T are converted to U in given sequence. The bold region is intron.
5' cUCGUAAUGGAAAGGUGCGAGUGGGCaCAGGCGCGGGGAAAAUGAGACUAUUUGUAGCUGACCCUC-3’
Matured mRNA removed Intron.
5' cUCGUAAUGGAAAGGUGCAGGCGCGGGGAAAAUGAGACUAUUUGUAGCUGACCCUC-3’
Amino - met Glu Arg Cys Arg Arg Cys Arg Arg Gly Glu Asn Glu Thr Ile Cys Ser - Carboxyl
Amino - M E R C R R C R R G E N E T I C S - Carboxyl
Cytosine added between first two codon
3' GCGGAGATgAGCATTACCTTTCCACGCTCACCCGtGTCCGCGCCCCTTTTACTCTGATAAACATCGACTGGGAG-5'
PremRNA
5’-CGCCTCGAcTCGTAATGGAAAGGTGCGAGTGGGCaCAGGCGCGGGGAAAATGAGACTATTTGTAGCTGACCCTC-3’
Matured mRNA
5’-CGCCTCGAcTCGTAATGGAAAGGTGCAGGCGCGGGGAAAATGAGACTATTTGTAGCTGACCCTC-3’