2 genes on one plasmid

[M. Alexeyev]

In article <48ffa7$a8h at biovax.biobase.dk>, wind at biobase.dk (Troels Wind) wrote:

> nathan (nathan at xyppp38.bms.com) wrote:
> : >>> On 14 Nov 1995 18:01:06 -0600, corboy at utdallas.edu said:
> 
> 
> :       Are you sure you need to use two promoters?  I know of at
> : least two systems where a single promoter will promote expression of
> : at least two genes (lac promoter in expression of antibody fab
> : fragments, t7 promoter: will promote expression of genes until t7
> : terminator is present)
> 
> : Someone correct me if I am wrong...
> 
> : nathan

I am not sure what system an original post was talking about, but you may
surely run into a problem with expression of two genes from the single
promoter in a plant system were bicistronic mRNAs are not transcribed
efficiently (I can dig out a reference). I am not sure about mammalian
systems were multicistronic mRNAs are also quite uncommon (if present at
all). I think, it may have something to do with cap-ribosome subunits
interaction during translation initiation. This could make translation of
distal gene problematic if ribosomes tend to fall of mRNA after meeting a
termination  codon.
M.A.