You have isolated another cDNA clone of the CRABS CLAW gene from ...

Question

You have isolated another cDNA clone of the CRABS CLAW gene from a cDNA library constructed using the vector shown in Problem 18. The cDNA was directionally cloned using the EcoRI and XhoI sites. You sequence the recombinant plasmid using primers complementary to the T7 and T3 promoter sites flanking the MCS (the positions of these sequences are shown in the figure in Problem 18). The first 30 to 60 bases of sequence are usually discarded since they tend to contain errors.

Can you identify the start of the coding region in the end of the gene? What does the sequence preceding the start codon represent?

Accepted Answer

Hi, everybody. Welcome back. Here's the next question which the following is a sequence motif that is commonly found in UIC M R N A molecules immediately surrounding the start codon A U G of protein coding regions. Choice A tata box, choice B cat box. That's CAA T box, choice C Kozak sequence or choice D the G C box. Well, the sequence motif or conserved sequence that is immediately in front of the start codon of a protein coding region is code is choice C the Cosac sequence, this comes right at that plus one, uh start A U G of where you have the start of a coding region. So helps to initiate translation accurately and efficiently. So enhancing that process of translation. When we look at our other answer choices, hoda box, cat box and G C box. Hopefully those are familiar to us as all being promoter elements. And of course, promoter elements help to enhance not the process of translation, but they are involved in the initiation of the process of transcription. So transcribing the DNA into the messenger R N A. So our other answer choices are incorrect because they're involved in transcription whereas we're looking for the consensus sequence that helps to initiate translation and that is choice c the Kozak sequence. See you in the next video.

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