Section Oral and Diagnostic Sciences, Columbia University College of Dental Medicine, New York.
J Oral Microbiol. 2011 Mar 9;3. doi: 10.3402/jom.v3i0.5764.
Porphyromonas gingivalis strains are shown to invade human cells in vitro with different invasion efficiencies, varying by up to three orders of magnitude.
We tested the hypothesis that invasion-associated interstrain genomic polymorphisms are present in P. gingivalis and that putative invasion-associated genes can contribute to P. gingivalis invasion.
Using an invasive (W83) and the only available non-invasive P. gingivalis strain (AJW4) and whole genome microarrays followed by two separate software tools, we carried out comparative genomic hybridization (CGH) analysis.
We identified 68 annotated and 51 hypothetical open reading frames (ORFs) that are polymorphic between these strains. Among these are surface proteins, lipoproteins, capsular polysaccharide biosynthesis enzymes, regulatory and immunoreactive proteins, integrases, and transposases often with abnormal GC content and clustered on the chromosome. Amplification of selected ORFs was used to validate the approach and the selection. Eleven clinical strains were investigated for the presence of selected ORFs. The putative invasion-associated ORFs were present in 10 of the isolates. The invasion ability of three isogenic mutants, carrying deletions in PG0185, PG0186, and PG0982 was tested. The PG0185 (ragA) and PG0186 (ragB) mutants had 5.1×10(3)-fold and 3.6×10(3)-fold decreased in vitro invasion ability, respectively.
The annotation of divergent ORFs suggests deficiency in multiple genes as a basis for P. gingivalis non-invasive phenotype.
牙龈卟啉单胞菌株在体外以不同的入侵效率侵入人体细胞，相差可达三个数量级。
我们检验了这样一个假设，即与入侵相关的菌株间基因组多态性存在于牙龈卟啉单胞菌中，并且推测与入侵相关的基因可能有助于牙龈卟啉单胞菌的入侵。
使用一个侵袭性（W83）和唯一可用的非侵袭性牙龈卟啉单胞菌株（AJW4）以及全基因组微阵列，然后使用两种不同的软件工具，我们进行了比较基因组杂交（CGH）分析。
我们在这些菌株之间发现了 68 个注释和 51 个假设的开放阅读框（ORF）存在多态性。其中包括表面蛋白、脂蛋白、荚膜多糖生物合成酶、调节蛋白和免疫反应蛋白、整合酶和转座酶，它们通常具有异常的 GC 含量，并在染色体上聚集。选择 ORF 的扩增用于验证该方法和选择。选择了 11 个临床菌株来研究所选 ORF 的存在情况。在 10 个分离株中发现了假定的与入侵相关的 ORF。三个同源突变体的入侵能力被测试，它们在 PG0185、PG0186 和 PG0982 中缺失。PG0185（ragA）和 PG0186（ragB）突变体的体外入侵能力分别降低了 5.1×10(3)-倍和 3.6×10(3)-倍。
不同 ORF 的注释表明多个基因的缺陷是牙龈卟啉单胞菌非侵袭表型的基础。
