express protein with many rare codons - (Feb/02/2010 )

Hi all

I'm trying to express domain/fragment of protein ligated to pGEX-6P.
this sequence contains many rare codone for example:
CGG GGG = 1
CGG CGG CGG = 1
CGG CCC = 1
they are about 15 codons. I tried in BL21 (DE3) and Rosetta but it seems there is nothing.
I tried different temp and IPTG conc. but unfortunately I can't. when I checked the insoluble fraction I found a band at the right size of my protein but I don't know from the whole story if it easy to express protin like this one.
any suggestions or guide I will appreciate any reply.

Thanks in advance

Are these codon optimised for bacterial expression? Sometimes it might be better to check if the cDNA has been optimised for a specific expression system.
This might not be the reason for no expression but could help.