The Type 2 Capsule Locus of Streptococcus pneumoniae

Abstract

The type 2 capsule locus of Streptococcus pneumoniaewas characterized in Avery’s strain D39, which is the parent strain of the standard transformation recipients currently used in pneumococcal research and is largely used as a virulent strain in studies on the pathogenesis of pneumococcal infections. The capsule locus was sequenced by using a 21.7-kb PCR fragment from the D39 genome as a template. Sequence data analysis showed the presence of 18 open reading frames, 17 of which have the same direction of transcription and all of which are potentially involved in capsule biosynthesis. It was also shown that R36A and R6, which are unencapsulated (rough) derivatives of D39, carry a 7,504-bp deletion involving nine capsule genes.

Recent trends on the molecular biology of pneumococcal capsules, lytic enzymes, and bacteriophage

“…Sequence conservation among serotype‐specific genes is particularly evident in the case of group 19 pneumococci [20] though the fifth gene of the cap/cps locus, encoding a glucosyltransferase catalyzing the transfer of glucose‐1‐phosphate to a lipid carrier [21], is conserved at least in types 2, 4, 14, 19F/A/B/C, 23F, and 33F. Noticeably, the genes cap1K, cps2K , and cap3A , encoding otherwise biochemically identical enzymes, namely a uridine diphosphoglucose (UDP‐Glc) dehydrogenase, were clearly divergent in types 1, 2, and 3, respectively, although cap8L that codes for the type 8 UDP‐Glc dehydrogenase was 92% identical to cps2K [22,23].…”

Comparative genomics for identification of clone-specific sequence blocks in Streptococcus pneumoniae

“…Partial genomes of two di¡erent pneumococcal strains were identi¢ed in the public patent database, downloaded, scanned, formatted to a multi-FASTA text ¢le, and ¢nally transformed into a searchable database. Pneumococcal strains were (i) the type 3 clinical isolate 0100993 [19], and (ii) the standard transformation recipient R6, which is the rough derivative of Avery's type 2 strain D39 [15,20]. Three di¡erent patents (WO9743303, WO9819689, WO9823631) [21^23] containing sequences of strain 0100993 were identi¢ed, all having SmithKline Beecham Corporation as the applicant ( Table 1).…”

Capsule genes ofStreptococcus pneumoniaeinfluence growthin vitro

“…The first four genes, cpsA-cpsD, play a role in the regulation of capsule expression (Bender et al, 2003;Morona et al, 2004). For example, the serotype 2 capsule operon of D39 consists of 17 capsule genes (cpsA-E, cpsT, cpsF-K, cpsP, and cpsL-O) (Iannelli et al, 1999). The first four genes (cpsA-D) are involved in the regulation and export of the capsular polysaccharide.…”