Hi Rachel,
In(2LR)CyO-P20 is a CyO derivative in which a 20 kb transposon from
ca. 72 to ca. 92 on the molecular map of dpp (St. Johnston et al., 1990)
that covers all functions mediated by the dppHin and dppshv region
is inserted into CyO (polytene insertion position unknown). The 20 kb
fragment is from a SalI digest of genomic DNA (I think from our dpp+
dp cn bw isogenic strain that was also used as the RNA source for Nick
Brown's cDNA libraries).
In(2LR)CyO-P20 completely suffices for dpp function, even in the absence
of any other copies of dpp in the genome. (In other words, it acts as
if it is disomic for the dppHin+ function.)
This construct was made by Rick Padgett while he was a postdoc in my
laboratory. I would like this personal communication to be cited
as Padgett and Gelbart, pers. comm. to FlyBase.
I am cc'ing this message to Rick in case he wishes to add to or amend
anything I wrote.
Bill