Question

Artificially synthesized genes without noncoding sequences often fail to yield proteins when placed inside a cell, because

• A. They curl up
• B. mRNAs are not capable of protein formation
• C. They bind to DNA
• D. Are not transcribed

Answer 1

The correct option is B mRNAs are not capable of protein formation

An artificially synthesized gene first undergo the process of transcription to produce the mRNA which is transported to cytoplasm through nuclear pore. The process of protein synthesis takes place in cytoplasm only. Here, artificially synthesized genes lack non-coding sequences and transcribed mRNA does not undergo the processing as the natural hnRNA usually undergo to produce mRNA. The hnRNP proteins, associated with processing, also contain nuclear export signals and function as carriers of mRNAs during their export to the cytoplasm. A gene without noncoding region does not code for these processing and signalling proteins and hence the resultant mRNA fail to cross the nuclear envelop where protein synthesis occurs. Correct option is B.