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    I really don't understand the spread on golden rice. How are the beta carotene genes switched on by adding genes for different enzymes?
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    (Original post by celina10)
    I really don't understand the spread on golden rice. How are the beta carotene genes switched on by adding genes for different enzymes?
    Hello,

    I'm guessing that once the desired gene is inserted into rice embryos, it would need to be switched on for beta-carotene to be produced, which would give rice its "golden" colour.
    I've had a look at the page spread, and I think that when they first produced golden rice using a gene from daffodils, the gene coded for enzymes (e.g. phytoene synthase) that would be needed for the biosynthesis of beta carotene.
    Without these enzymes, beta-carotene could not be produced.

    I hope that helps - I'm sorry for the delayed reply!

    Zef1995
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    (Original post by zef1995)
    Hello,

    I'm guessing that once the desired gene is inserted into rice embryos, it would need to be switched on for beta-carotene to be produced, which would give rice its "golden" colour.
    I've had a look at the page spread, and I think that when they first produced golden rice using a gene from daffodils, the gene coded for enzymes (e.g. phytoene synthase) that would be needed for the biosynthesis of beta carotene.
    Without these enzymes, beta-carotene could not be produced.

    I hope that helps - I'm sorry for the delayed reply!

    Zef1995
    The genes for beta carotene are switched on in the green parts of the plant but switched off in the grains, so are these genes switched on?
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    (Original post by zef1995)
    Hello,

    I'm guessing that once the desired gene is inserted into rice embryos, it would need to be switched on for beta-carotene to be produced, which would give rice its "golden" colour.
    I've had a look at the page spread, and I think that when they first produced golden rice using a gene from daffodils, the gene coded for enzymes (e.g. phytoene synthase) that would be needed for the biosynthesis of beta carotene.
    Without these enzymes, beta-carotene could not be produced.

    I hope that helps - I'm sorry for the delayed reply!

    Zef1995
    Actually I think I understand, the genes they extracted from the daffodils and bacterium are inserted next to a promoter sequence associated with endosperm developed, so this makes sure the inserted genes are switched on and expressed. Is this right?
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    (Original post by celina10)
    Actually I think I understand, the genes they extracted from the daffodils and bacterium are inserted next to a promoter sequence associated with endosperm developed, so this makes sure the inserted genes are switched on and expressed. Is this right?
    I don't want to say you're wrong, because there's a good chance you may be right, but I'm not too familiar with the promoter sequence part :/
    Please feel free to correct me if I'm wrong, but with the genes they extract from daffodils, I had a feeling that they insert them into plasmids from bacteria, get the bacteria to uptake the plasmids, and then culture the bacteria that have taken up the plasmids. Once they have done this, they insert the bacteria into a pert dish containing rice embryos...in which some of the embryos become infected with the bacteria. The rice embryos that become infected with the bacteria are the ones that are grown into full adult plants to produce the golden rice.
    I do agree with what you're saying even though I'm not completely sure what all of it means (I apologise) - there is likely to be something that ensures that the gene/genes for the enzymes that produce beta-carotene are expressed.
    I was thinking, if they have to cut out a gene to insert the gene from the daffodils in, maybe they cut out a gene that is almost always expressed, so when they replace it with the one from daffodils, that one is likely to be expressed to, so the beta-cartene will be produced. Do you reckon that is a possibility?
    I'm sorry about the essay; I hope I haven't confused you at all!
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    (Original post by zef1995)
    I don't want to say you're wrong, because there's a good chance you may be right, but I'm not too familiar with the promoter sequence part :/
    Please feel free to correct me if I'm wrong, but with the genes they extract from daffodils, I had a feeling that they insert them into plasmids from bacteria, get the bacteria to uptake the plasmids, and then culture the bacteria that have taken up the plasmids. Once they have done this, they insert the bacteria into a pert dish containing rice embryos...in which some of the embryos become infected with the bacteria. The rice embryos that become infected with the bacteria are the ones that are grown into full adult plants to produce the golden rice.
    I do agree with what you're saying even though I'm not completely sure what all of it means (I apologise) - there is likely to be something that ensures that the gene/genes for the enzymes that produce beta-carotene are expressed.
    I was thinking, if they have to cut out a gene to insert the gene from the daffodils in, maybe they cut out a gene that is almost always expressed, so when they replace it with the one from daffodils, that one is likely to be expressed to, so the beta-cartene will be produced. Do you reckon that is a possibility?
    I'm sorry about the essay; I hope I haven't confused you at all!
    Yeah I agree, I think what both of us said kind of ties in together. The genes from the daffodils are placed into the bacterium and then cultured and then the genes that came from the daffodil and bacterium are then inserted into the endosperm. But they're inserted near the promoter sequence that switches on the genes associated with endosperm development. And obviously the genes for endosperm development would have to be switched on eventually to ensure the endosperm develops, so the genes that have been inserted will also be switched on. So basically the beta carotene is synthesised as the endosperm develops.
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    (Original post by celina10)
    Yeah I agree, I think what both of us said kind of ties in together. The genes from the daffodils are placed into the bacterium and then cultured and then the genes that came from the daffodil and bacterium are then inserted into the endosperm. But they're inserted near the promoter sequence that switches on the genes associated with endosperm development. And obviously the genes for endosperm development would have to be switched on eventually to ensure the endosperm develops, so the genes that have been inserted will also be switched on. So basically the beta carotene is synthesised as the endosperm develops.
    I think you're right, by combining our knowledge I think we've sussed it
    I agree with you, but I was just wondering, is the promoter sequence to do with a stretch on DNA called the operon, which controls the expression of "structural" genes? I've studied something called the lac operon, and that had a promoter sequence on it.
    With respect to the endosperm, the gene for beta-carotene is transcribed to produce the beta-carotene, and i assume that it gets passed onto the endosperm too?
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    (Original post by zef1995)
    I think you're right, by combining our knowledge I think we've sussed it
    I agree with you, but I was just wondering, is the promoter sequence to do with a stretch on DNA called the operon, which controls the expression of "structural" genes? I've studied something called the lac operon, and that had a promoter sequence on it.
    With respect to the endosperm, the gene for beta-carotene is transcribed to produce the beta-carotene, and i assume that it gets passed onto the endosperm too?
    Yep, two brains are better than one.

    Yeah it's that lac operon stuff, the promoter sequence has to be exposed in order for the structural genes to be transcribed and translated. So the genes would probably be inserted amongst those structural genes (,but for endosperm development). I agree with the last bit too, I'm assuming you mean that the endosperm can now accumulate beta carotene due to the genes for it being inserted there.
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    (Original post by celina10)
    Yep, two brains are better than one.

    Yeah it's that lac operon stuff, the promoter sequence has to be exposed in order for the structural genes to be transcribed and translated. So the genes would probably be inserted amongst those structural genes (,but for endosperm development). I agree with the last bit too, I'm assuming you mean that the endosperm can now accumulate beta carotene due to the genes for it being inserted there.
    It appears so, yay for combined knowledge :P

    Ah yes, I am familiar with that, that makes sense! I guess if that is how they do it, then the gene that they cut out originally is connected to an operon in some way?
    Yeah pretty much, the gene for beta-carotene could be passed on in the endosperm, as well as being present in the rice plants themselves.
 
 
 
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