Duplication and differential expression of hemagglutinin genes in Porphyromonas gingivalis

Abstract

A third hemagglutinin gene, defined as hagC, was cloned from Porphyromonas gingivalis 381 and sequenced. This gene was found to encode a protein highly homologous (98.6%) to the previously reported HagB hemagglutinin protein. The upstream and downstream regions of hagB and hagC were found to share less than 40% homology compared with 99% for their open reading frames. The antigenic relationship between the two hemagglutinins was demonstrated by Western blot analysis. When expressed in an in vitro transcription-translation system, both genes encoded a protein with a molecular mass of 49 kDa. As determined by reverse transcription polymerase chain reaction, the steady-state levels of hagB and hagC mRNAs were found to vary according to the growth phase and hemin concentration. The amount of transcripts decreased in hemin-limited conditions or in the absence of hemin. Furthermore, hagB mRNAs were detected in the early logarithmic growth phase compared with the hagC transcripts, which were detected only in the mid-exponential phase of growth.

Genetic Analyses of Proteolysis, Hemoglobin Binding, and Hemagglutination of Porphyromonas gingivalis

“…3 Taken together, it is unlikely that fimbriae are responsible for hemagglutination of P. gingivalis, even if synthetic peptides derived from the amino acid sequence of fimbrilin possess hemagglutinating activity (44). The expression of hagB and hagC depends on the phase of bacterial growth and on the levels of hemin (45). Therefore, we cannot rule out the possibility that these genes contribute to the hemagglutination of P. gingivalis under conditions that differ from those used in this study.…”

Comprehensive Transcriptome Analysis of the Periodontopathogenic Bacterium Porphyromonas gingivalis W83

“…The sequence homology explains the similar differential expression patterns. Both the growth phase and the level of hemin have been reported to affect the transcription of these two genes (43). The hemin levels in the TSB and MIN media were similar, but the lower mRNA abundance in MIN may reflect the slower growth caused by the nutrient-limited condition.…”

“…The two genes hagC and hagB display a high degree of sequence homology and are coding for almost identical proteins (43). The expression of these genes was upregulated in TSB compared to MIN.…”

Human α- and β-Defensins Bind to Immobilized Adhesins fromPorphyromonas gingivalis

“…Attachment and invasion of the organism are promoted by adhesins, including fimbriae (16,59) and hemagglutinins (27,30,37,40). Local tissue damage and evasion of host defense mechanisms are facilitated by capsular polysaccharides (34,55), lipopolysaccharide (2,3,58), and proteolytic enzymes (4,5,13,46,53,54).…”