Speed of Transport of mRNA Through the Nuclear Pores

Speed of Transport of mRNA Through the Nuclear Pores -...

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Speed of Transport of mRNA Through the Nuclear Pores Evidence suggests that this time may vary. Longevity of mRNA Messenger RNA can last a long time. For example, mammalian red blood cells eject their nucleus but continue to synthesize hemoglobin for several months. This indicates that mRNA is available to produce the protein even though the DNA is gone. Ribonucleases Ribonucleases are enzymes that destroy mRNA. Messenger RNA has noncoding nucleotides at either end of the molecule. These segments contain information about the number of times mRNA is transcribed before being destroyed by ribonucleases. Hormones stabilize certain mRNA transcripts. Example Prolactin is a hormone that promotes milk production because it affects the length of time the mRNA for casein (a major milk protein) is available.
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Unformatted text preview: Ribonucleases destroy the mRNA. Prolactin is a hormone that prevents destruction of the mRNA. Translational Control These mechanisms prevent the synthesis of protein. They often involve protein factors needed for translation. Preventing Ribosomes From Attaching Proteins that bind to specific sequences in the mRNA and prevent ribosomes from attaching can prevent translation of certain mRNA molecules. Initiation Factors Initiation factors are proteins that enable ribosomes to attach to mRNA. These factors can be produced when certain proteins are needed. For example, the eggs of many organisms contain mRNA that is not needed until after fertilization. At this time, an initiation factor is activated...
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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Speed of Transport of mRNA Through the Nuclear Pores -...

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