Analysis of transcription of the S.
agalactiae type Ia cps gene cluster. (A) Northern
blotting analysis of total RNA of S. agalactiae type Ia
strain OI1. RNA was hybridized with cpsIaA (lane 1),
orf1 (lane 2), cpsIaA upstream (lane 3),
ung (lane 4), and ung downstream (lane 5) probes.
In lane 6, total RNA was electrophoresed on a 1% agarose gel
containing 2.2 M formaldehyde and detected by ethidium bromide
staining. With cpsIaA, orf1 and ung
probes, a long transcript which seemed to correspond to the
cpsIa gene cluster was observed (band a). Such a band was
not observed with cpsIaA upstream and ung
downstream probes. The smeared band in lane 1 (band b) may be
degradation products. Band c in lane 2 seemed to correspond to a
transcript from the orf1 gene. Band d in lane 3 seemed to be
produced from the upstream region of cpsIaA. Unknown bands (e) were
observed with several different probes. The sizes of RNA standards
(Takara) are indicated. (B) RT-PCR of cps genes.
Amplification of the cpsIaE locus was performed with RT
reaction products produced by using the ung 3′-downstream
primer (lane 1), the ung internal primer (lane 2), the
orf1 3′-end primer (lane 3), the neuA internal
primer (lane 4), and the cpsIaJ 3′-downstream primer (lane
5). Amplification was also performed with a sample that was not reverse
transcribed as a negative control (lane 6). cpsIaE (lane 8),
cpsIaD to IaE (lane 9), cpsIaB to
IaE (lane 10), cpsIaA (lane 14), and the upstream
region of cpsIaA (lane 15) were amplified from the RT
reaction product produced with the cpsIaJ 3′-downstream
primer. These loci were also amplified by using chromosomal DNA (1
μg) of S. agalactiae type Ia as the template (lanes 7 and
11, cpsIaE; lane 12 cpsIaD to IaE;
lane 13, cpsIaB to IaE; lane 16,
cpsIaA; lane 17, upstream region of cpsIaA) as
controls. The direction and start sites of the RT reaction are
indicated by broken arrows. PCR-amplified regions are shown by solid
arrows. (C) Primer extension analyses of the transcriptional initiation
sites in the sequences upstream of the cpsIaA,
cpsIaE, and orf1 genes. The arrows indicate the
transcriptional start sites, and the −10 consensus sequences are also
shown.