TABLE 1.

Strains and plasmids used in this study

Strain or plasmid	Relevant featuresa	Reference
Strains
S. pneumoniae
R6	Unencapsulated derivative of D39	30
D39 (FP22)	D39 with cps gene locus replaced by Kmr cassette; template for Δcps PCR product	49
D39 ΔaliA	D39 with aliA gene replaced by Ermr cassette	32
TIGR4	Wild-type strain; serotype 4	62
TIGR4 (FP23)	TIGR4 with cps gene locus replaced by Kmr cassette	49
CP1250	Unencapsulated derivative of Rx and D39	51
E. coli
DH5α	Host for plasmids pR412T7 and pR410	24
L. lactis
LL108	Host for plasmid pNG8048E	42
Plasmids
pR412T7	Donor for mariner transposon, conferring Spr; contains T7 promoter; Ampr	12
pR410	Donor for mariner transposon, conferring Kmr; Ampr	61
pNG8048E	Replicating plasmid derived from pNZ8048; Ermr Cmr	33

^aKm^r, kanamycin resistance; Erm^r, erythromycin resistance; Sp^r, spectinomycin resistance; Amp^r, ampicillin resistance; Cm^r, chloramphenicol resistance.