Table 3

gad regulon components showing pH dependence under oxygen limitation.

Gene

Function

Log₂ Expression ratio

pH 5.7/pH 7.0

pH 7.0/pH 8.5

pH 5.7/pH 8.5

GadA region: 3650–3666 kb

slp

Outer membrane protein induced after carbon starvation

3.47

-1.82

1.64

dctR

Probable repressor of dctA dicarboxylate transporter gene

2.60

-1.00

1.59

yhiD

integral membrane protein related to MgtC.

2.26

-1.04

1.21

hdeB

Periplasmic chaperone of acid-denatured proteins

0.79

-0.55

hdeA

Periplasmic chaperone of acid-denatured proteins

0.74

-0.50

hdeD

Putative membrane transporter, H-NS repressed

2.30

-1.26

1.03

gadE

Required for stationary phase-induced, pH 5.5 growth medium-induced, and EvgA-induced acid resistance

3.19

-2.23

0.95

mdtE

MdtEF-TolC multidrug resistance efflux RND-type transporter; overexpression resistance to erythromycin, deoxycholate, octane and rhodamine

3.17

-1.59

1.58

mdtF

MdtEF-TolC multidrug resistance efflux RND-type transporter; overexpression resistance to erythromycin, deoxycholate, octane and rhodamine

2.58

-0.98

1.60

gadW

Positive AraC-type regulator of gadA and gadBC, in absence of gadX; repressor of gadX

2.70

-1.17

1.53

gadY

sRNA regulates gadX and gadY

3.17

-1.38

1.80

gadX

Positive transcriptional regulator of gadA and gadBC; repressed by HNS and GadW; stimulated by RpoS

2.66

-1.47

1.19

gadA

Glutamate decarboxylase isozyme

4.89

-3.46

1.43

GadB operon: 1567–1570 kb

gadB

Glutamate decarboxylase isozyme

3.21

-2.50

gadC

Glutamate transporter

3.73

-2.44

1.29

Hayes et al. BMC Microbiology 2006 6:89   doi:10.1186/1471-2180-6-89