Cosmid library, trans-acting factors

[astlab4]

Hi there!
......I'm looking for a human chromosome 6 cosmid librarary. Anybody there can 
advice me where I can get it?

I have another question: Is there any way to identify transcriptional factors 
by means of complementarity or rescue of mutants once that you have the 
promoter-enhancer?
I will try to explain: I already have identified a promoter or at least a 2 kb 
region upstream the +1 of my gene. If this region is introduced upstream of, 
let's say Beta-gal and then yeast or mammalian cells are cotransformed with an 
expression library, what are my chances to find a trans-activator?
The problem that I have is the limitation of tissue and haven't found any cell 
line expressing my gene; thats what  i thoght that perhaps in  this way could 
be easier to do. Any reference will be appreciated.
Thanks:
            ataulfo

      e-mail: mataulfo at darwin.bio.uci.edu