Table 1 Strains and plasmids used in this study

S. erythraea

A226

CGMCC 8279, an erythromycin low producer

China Pharmaceutical Culture Collection

ΔSACE_7301

A226 with SACE_7301 deleted

This study

ΔSACE_7301/pZMW

ΔSACE_7301 carrying pZMW

This study

ΔSACE_7301/pZMW7301

ΔSACE_7301 carrying pZMW7301

This study

A226/pZMW

A226 carrying pZMW

This study

A226/pZMW7301

A226 carrying pZMW7301

This study

A226/7301

A226 carrying pSET152-7301

This study

A226/2×7301

A226 carrying pSET152-2×7301

This study

A226/3×7301

A226 carrying pSET152-3×7301

This study

WB

CGMCC 8280, an erythromycin industrial overproducer

Anhui Wanbei Pharmaceutical Co., Ltd.

WB/7301

WB carrying pSET152-7301

This study

WB/2×7301

WB carrying pSET152-2×7301

This study

WB/3×7301

WB carrying pSET152-3×7301

This study

E. coli

DH5α

F recA lacZM15

[40]

BL21(DE3)

F-ompT hsdSB (rB-mB-) gal dcm (DE3)

Novagen

Plasmids

pUCTSR

pUC18 derivative containing a 1.36-kb fragment of a thiostrepton resistance cassette in the BamHI/SmaI sites

[41]

pUCTSR-Δ7301

pUCTSR carrying two 1.5-kb fragments of the flanking sequence of SACE_7301 gene

This study

pZMW

E. coli-S. erythraea integrative shuttle vector carrying PermE*

[42]

pZMW7301

pZMW carrying SACE_7301

This study

pBluescript II SK (+)

bla, lacZ orif1

Stratagene

pSK-7301

pBluescript II SK (+) carrying SACE_7301 under the control of PermE*

This study

pSET152

E. coli-S. erythraea integrative shuttle vector

[43]

pSET152-7301

pSET152 carrying SACE_7301 under the control of PermE*

This study

pSET152-2×7301

pSET152 carrying two extra copies of SACE_7301 under the control of PermE*

This study

pSET152-3×7301

pSET152 carrying three extra copies of SACE_7301 under the control of PermE*

This study

pET22b

T7 promoter, His-tag, kan

Novagen

pET22b-7301

pET22b carrying SACE_7301

This study

pET22b-bldD

pET22b carrying bldD

This study