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Joumana

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Posts posted by Joumana

  1. Human gene is not being expressed when it's inserted in bacterium plasmed. The reasons come from the differences in the gene expression between eukaryotic and prokaryotic.

     

    - First difference is in the promoter structure and position. I think this surly will effect the transcription. Prokaryotic promoter has different structure from Eukaryotic one. This will affect the recognition of the transcription factors. The position is also different. Prokaryote promoter locates 10 to 35 nt.

     

    - Second difference is in the RNA polymerase. In prokaryote there is only one type of RNA polymerase that does the transcription. While in eukaryotic there is three different RNA polymerases which means they are specialized for certain genes. Prokaryotic RNA will not recognize the special recognition signal in inserted human gene.

     

    - Third reason is bacteria (prokaryotic) gene have only exons, with no entrons. Therefore there is no splicing process in bacteria. Human gene has entrons and must be spliced.

     

    - Forth reason is some codons in bacteria code for different amino acid that human codons code for.

     

    This is my assumptions.

  2. hi all,

     

    I've question

    we have human gene (with its promoter , TE , ....ect ) which code for a certain protein inserted in plasmed of bacteria , but what happen is there was no expressing for this gene !!! ... why????

     

    -I think that may be mRNA degrated before translation by the action of nuclease enzymes. in other words, no capping or cleavage make the mRNA exposed to 3' exonuclease & 5' exonuclease.

     

    - OR may be because there is a gene control the splicing for this gene which is not transferred to plasmed. I mean there is other gene may code for protein control splicing in specific way for exons that stop the translation or produce inactive protein. is it possible ?!

     

    I hope someone help me in this question .

     

    Thank you ,

     

    Jumana

  3. you made me carious about your question ...

    you said:

    (imagine 50% of

    the cells have the good X copy inactivated), shouldn't women carrier

    of the disease at least express some symptoms

     

    The inactive X chromosome does not express the majority of its genes, unlike the active X chromosome
    Wikipedia.

     

    so there is some expression to some of inactive-X genes

    that's why the symptoms of such a disease may appear ..

     

    I'm waiting the experts answer ur qeus.s ...

  4. doctor said:

    Here is the question:

    Let's say you are visualizing a fixed cell and you stained for a certain protein. You found this protein on the cell surface (i.e. on the plasma membrane).

    This protein may have just been delivered to the plasma membrane (coming from the golgi), or it may have been at the membrane, recycled back to the inside of the cell, then recycled back to the surface.

    So, if you find a protein on the cell surface, how will you know whether it has been on the surface since it has been delivered there, or it has gone to the membrane then to the inside then back to the membrane?

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