Start codon after promoter - (May/22/2014 )

Dear all,

How far can you put the start codon (ATG codon) after the promoter? Is there a general rule, I am guessing its best that the ATG codon is as close as possible to the promoter sequence or does it not matter that much?

Can I have , for example 100 basepairs between the end of the promoter and the ATG codon?

thanks in advance
 

I think 100 bp will be fine.  If I remember the little I know about this topic correctly, then some mammalian promoters are several hundred bp 5' of the ATG.