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Polycistronic mRNA or mtDNA

  1. Apr 1, 2005 #1
    Hi everybody !

    I wonder, how do 2, 3, 4 or more :) different polypeptides arise from one polycistronic mRNA, when they are spaced with only one or two base pairs ? I’m referring here to mitochondrial mRNA (or prokaryote DNA).
    Which tool or mechanism recognizes this base pare as spacers and cuts polypeptide chain into more then one ?
     
  2. jcsd
  3. Apr 2, 2005 #2
    Since no one answered my first question, here’s the second, was my question to much elementary or easy so no one bothers, or no one knows the answer? :confused:

    Maybe you can help me to find a place were I can answer it?

    Thanks,
    Bye
    :smile:
     
  4. Apr 2, 2005 #3

    iansmith

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    polycistronic mRNA in bacteria and eucarya processing is different. In bacteria, only a ribosomal binding site is required in front of the second, third and ect open reading frame(s). For eucaryotes, it is a bit more complex.

    http://www.madsci.org/posts/archives/mar2001/985920332.Mb.r.html
     
  5. Apr 2, 2005 #4
    Thank you iansmith,
    So can I conclude that same mechanism applies for prokaryotes and mitochondria (only ribosomal binding site is required in front of the second, third and ect open reading frame(s)) ?
     
  6. Apr 2, 2005 #5

    iansmith

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    As far as I know, the mitochondiral polycistronic mRNA is often process into mRNA that encode only one protein. So mitochondrial polycistronic mRNA is not often process as one unit.

    Mitochondria polycistronic could be translated by ribosome using a similar mechanism (only need a RBS) that the one found in bacteria since the rRNA is quite similiar. I have not found any information regarding this mechanism.
     
  7. Apr 2, 2005 #6
    I came to this question during one lecture, in which one of my professors sad that most of 13 recognizable genes that code for polypeptides in mtDNA are transcribed into polycistronic mRNA, encoding parts spaced by only 1-2 bp.
    I’ve asked her the same question but I didn’t get answer (she just repeated part about organization of mtDNA :))
     
  8. Apr 3, 2005 #7
    Oh, so it goes like that, that makes sense. :smile:
    But how is mRNA processed into smaller fragments, restriction enzyme, maybe some kind of splice mechanism, or something else ?

    Regards!
     
  9. Apr 3, 2005 #8

    iansmith

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