help!!! for plasmid YIElD

[Takbum Ohn]

Hello!! netters...

I have cloned a cell wall hydrolase (probably toxic to E. coli host) from
Moraxella sp. and now, I subcloned the insert as short as 1 kb. 

The subclone expressed the gene very highly  but, oddly, the copy of the
subclone plasmid became very low. 

I don't know what make my plasmid like that.

The mother plasmid is pT7T3 19u, a high-copy number phasimid vector.

Any help would very appreciated.

Thanks..

Tak-Bum Ohn
Department of Biology
Hanyang University
KOREA

Personal E. mail address: ahnss at hitel.kol.co.kr