Hi everyone A compilation of replies to my question about the beta-gal gene for fusions follows; From: ROSENKRANTZ at Gems.VCU.EDU; Lenny Guarente at MIT has the pLG669Z lacZ fusion vector, which is a little different than the pMC's (Casadaban lacZ vectors) in having a bit of lacI as a linker. I have, but you might want to get directly from him.