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Oligodeoxynucleotide probes were developed for identification of the periodontal bacteria Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, B. intermedius types I and II, B. forsythus, Eikenella corrodens, Fusobacterium nucleatum, Haemophilus aphrophilus, Streptococcus intermedius, and Wolinella recta. Probes were designed by sequencing the 16S rRNA for each bacterium, identifying hypervariable regions, and chemically synthesizing species-specific probes. These probes were specific when tested against a panel of nucleic acids from closely related bacteria.

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Human papillomavirus 16 (HPV-16) early genes were tested for their ability to transform primary human embryonic fibroblasts (WI38) or to extend the life span of the fibroblasts. The expression plasmids containing the transcriptional unit for the HPV-16 subgenomic DNA fragments controlled by the simian virus 40 promoter were introduced into W138 cells with the aid of neomycin selection, and the drug-resistant cells that survived long-term culture were characterized. The fragments containing E6E7 open reading frames (ORFs) intact were found to be capable of extending the life span of W138 cells. From the results obtained with frameshift mutations in either ORF and from those obtained by cotransfection with the separate plasmids containing E6 and E7 ORFs, it was concluded that HPV-16 transformation (extension of the life span) of human fibroblasts requires expression of genes E6 and E7.

The E6 oncoprotein of human papillomavirus type 16 (HPV 16) [151amino acids (AA) long] contains four metal-binding motifs, C-X-X-C, and is postulated to form two 29-AA finger-like structures in the N-terminal and C-terminal halves, which mediate degradation of p53 and binding to p53, respectively. We constructed a series of E6 mutants with single-AA substitutions in these finger regions (AAs 34-62 and 107-135) and examined their transforming function for human embryonic kidney (HEK) cells in conjunction with HPV 16 E7 and their interaction with human p53 in vitro. The mutants with substitution of L for F-37, G for L-50, S for Y-54, and P for L-110, which did not transform HEK cells, showed markedly lowered activity to direct degradation of p53. The mutants with substitutions of G for R-39, G for V-42, G for Y-43, L for F-47, and G for V-53 lost the transforming function, but they could mediate degradation of p53 at levels comparable to the activities of the wild-type and transforming mutants. Like the wild type, all of the E6 mutants were localized by immunofluorescence to the nuclei of human TS21B cells or monkey COS-1 cells, except for the E6 mutant with substitution of G for Y-43 whose expression was undetectable. The levels of E6 mutants metabolically labeled in COS-1 cells were comparable to those of the transforming E6s. The data indicate that E6-directed degradation of p53 is necessary but not sufficient for HPV 16-mediated transformation of of HEK cells.

A turbid-plaque-forming mutant (pm522) of human papovavirus BK, which has a small deletion at about 0.7 map unit and grows somewhat more slowly in human cells than does wild-type BK virus, transformed hamster and rat cells in culture much more efficiently than did wild-type virus. Another plaque morphology mutant, pm525, forming turbid plaques larger than those of pm522 also had a high transforming capacity. The similar difference in transforming capability between wild-type and plaque morphology viruses was observed with DNAs extracted from virions. Recombinant viruses were constructed from the wild-type DNA fragment lacking HindIII-C (0.62 to 0.73 map unit) and pm522 HindIII-C (including the origin of replication) by the molecular cloning method. Characterization of the recombinants showed that the change near the origin of DNA replication was responsible both for the altered plaque morphology and for the enhanced transforming capacity of the BK virus mutant.