Key insight made in control of protein translation
You may (or may not) remember from high school biology that DNA contains the instructions for life. Genes within the DNA are the recipes for every single protein in our bodies, and every cell contains the same, complete set of DNA. But since all cells are obviously not all the same, how do they make the specific proteins that distinguish them?
"What makes them different from one another is the decision to 'turn on' or 'express' specific genes and turn off others. This gives each cell its unique array of proteins," senior researcher in the study Geraldine Seydoux said about how this decision is made.
For biologists, the central dogma of life is the following: DNA is transcribed into RNA, which is then translated into a protein. However, in DNA, not all of the As, Ts, Gs and Cs code for proteins. In fact, a significant amount is never translated into proteins at all, including "untranslated regions," or UTRs, which are found at the beginning and end of every gene and RNA sequence.
DNA is always read in the same direction from the 5' end to the 3' end. Therefore, when DNA is being transcribed into mRNA, the transcribing enzymes first read the 5' UTR, then the actual gene and finally the 3' UTR.
Sequences known as promoters are located before the 5' UTR on the DNA and decide whether to transcribe the DNA into RNA using proteins known as transcription factors. After transcription, the cell again needs to decide whether to translate that RNA into a protein. "3' UTR sequences help decide whether the RNA is translated, stored for a while or even degraded," Seydoux said.
So which region, the promoter or the 3' UTR, is more involved in regulating protein? Surprisingly, it was the 3' UTR. It would seem that the most efficient way of regulating a gene is using the promoter - why bother making RNA if you're not going to use it to make proteins?
The reality is different from what one might expect. "Many genes are transcribed all the time, and the decision to make the protein is made at the RNA level, not at the DNA level," Seydoux said.
"What makes them different from one another is the decision to 'turn on' or 'express' specific genes and turn off others. This gives each cell its unique array of proteins," senior researcher in the study Geraldine Seydoux said about how this decision is made.
For biologists, the central dogma of life is the following: DNA is transcribed into RNA, which is then translated into a protein. However, in DNA, not all of the As, Ts, Gs and Cs code for proteins. In fact, a significant amount is never translated into proteins at all, including "untranslated regions," or UTRs, which are found at the beginning and end of every gene and RNA sequence.
DNA is always read in the same direction from the 5' end to the 3' end. Therefore, when DNA is being transcribed into mRNA, the transcribing enzymes first read the 5' UTR, then the actual gene and finally the 3' UTR.
Sequences known as promoters are located before the 5' UTR on the DNA and decide whether to transcribe the DNA into RNA using proteins known as transcription factors. After transcription, the cell again needs to decide whether to translate that RNA into a protein. "3' UTR sequences help decide whether the RNA is translated, stored for a while or even degraded," Seydoux said.
So which region, the promoter or the 3' UTR, is more involved in regulating protein? Surprisingly, it was the 3' UTR. It would seem that the most efficient way of regulating a gene is using the promoter - why bother making RNA if you're not going to use it to make proteins?
The reality is different from what one might expect. "Many genes are transcribed all the time, and the decision to make the protein is made at the RNA level, not at the DNA level," Seydoux said.
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