Richard A. Krzyzek

Relationship between Condylomata and Laryngeal Papillomata: Clinical and Molecular Virological Evidence

In a survey of 49 papilloma patients accurate maternal condyloma history was obtained in 31 instances and of these, 21 were positive for the presence of condyloma during pregnancy or parturition. Molecular virological studies indicate that positive hybridization could be demonstrated to human papilloma virus 2 in both laryngeal papilloma and condyloma by the Southern blot technique. Immunoperoxidase staining illustrated the presence of virus-related particles only near the surface of the mucous membrane papilloma, which is in contrast to the definite staining of the stratum granulosum and stratum corneum of verrucae. Collectively this provides convincing evidence for an etiological relationship between condyloma acuminata and some laryngeal papillomata. The highly contagious nature of human papilloma virus infection is discussed and the possibility of cesarian section in the presence of active condyloma must be considered.

Identification of a novel human papilloma virus in cutaneous warts of meathandlers.

Abstract Papillomavirus DNA from common skin warts of four meathandlers has been characterized and compared to the DNA genomes of known human cutaneous papillomaviruses. Virus was purified from one of the human papilloma samples and was found to exhibit a restriction endonuclease cleavage pattern distinct from those of known human papillomaviruses (HPV). Moreover, viral DNA extracted from papillomas from the other three patients exhibited sequence homology and restriction endonuclease cleavage patterns similar to this novel viral DNA. In addition to this unique HPV, one of the patients also contained a second species of HPV which was related to, yet distinct from, HPV-2, a species of HPV associated with common cutaneous warts in man. Finally, employing the Southern transfer procedure and stringent hybridization conditions, each meathandler HPV DNA studied was found to be unrelated to the major species of bovine papillomavirus, types 1 and 2.

Post-transcriptional control of avian oncornavirus transforming gene sequences in mammalian cells.

TRANSFORMATION of cells by RNA tumour viruses generally results in a stable association of the viral genome with the morphologically altered cell. Studies with temperature-sensitive mutants of these viruses have clearly demonstrated that viral-specific gene functions are required for establishment and maintenance of the transformed phenotype1–6. For avian oncornaviruses the transforming (sarcoma) gene sequences are required for both transformation of cells in tissue culture and the production of tumours in animals7–8. In all of the oncornavirus-infected mammalian cell systems studied to date regulation of expression of the avian RNA tumour virus transforming gene sequences seems to be under the influence of transcriptional control mechanism(s) because appreciable differences in the amount of sarcoma-specific RNA can be detected in cells exhibiting normal and transformed phenotypes. For instance, the amount of sarcoma-specific RNA was substantially reduced in most revertant subclones of Rous sarcoma virus (RSV)-infected hamster cells compared with the original transformed clones9–11. Although several revertant RSV-hamster cells exhibited less dramatic differences in sarcoma-specific RNA, it nevertheless seemed that the transformed phenotype was directly related to the extent of transcription of the virus transforming gene sequences in this transformed/revertant cell system. A similar correlation between the amount of sarcoma-specific viral RNA and the malignant phenotype was recently reported for murine sarcoma virus-infected cells12.

Effect of arginine and canavanine on arginine messenger RNA synthesis.

Summary The level of messenger RNA for the arg ECBH gene cluster in Escherichia coli was determined by hybridization of 3 H-pulse-labeled RNA with DNA from 80darg. L-Arginine repressed the level of hybridizable message 7 to 24 fold lower than that observed in arginine-deprived cells. Added L-canavanine had little effect on the level of hybridizable message during arginine-deprivation. Our data suggest that the arginine regulon is repressed at both the level of transcription and translation.

Loss of tumorigenicity correlates with a reduction in pp60src kinase activity in a revertant subclone of avian sarcoma virus-infected field vole cells.

We have recently isolated an interesting revertant subclone (revertant 866-4) of ESV-infected field vole cells that is indistinguishable from uninfected vole cells with respect to its lack of transformed cell properties. These revertants are not only normal morphologically, but they do not grow in soft agar and are nontumorigenic in athymic nude mice. Despite this lack of transformed cell properties, we have found that this cell line still contains pp60src at concentrations (0.30 microgram/mg cell protein) similar to those (0.13-0.42 microgram/mg cell protein) found in transformed and morphologically reverted, but tumorigenic vole cells (partial revertants). However, the most interesting aspect of this newly isolated subclone is the marked reduction in its pp60src kinase activity (2--3%) when compared with the specific activity of pp60src immunoprecipitated from transformed and partially revertant vole cell lines. Since the reduction in pp60src kinase activity strongly correlates with the loss of tumorigenicity in this particular revertant cell line, these data support the contention that this enzymatic activity is a crucial factor in the tumorigenic conversion of cells by avian sarcoma virus. Proteolytic peptide analysis of the structure of pp60src from revertant 866-4 indicates that it is similar to pp60src obtained from avian sarcoma virus-transformed chick embryo fibroblasts. Moreover, the reduction in kinase activity does not appear to be due to a lack of phosphorylation of the tyrosine residue in pp60src. Thus neither an obvious structural alteration nor a reduction in phosphorylation of pp60src appears responsible for the reduced kinase activity observed, suggesting that some as of yet undetermined feature of pp60src can influence the pp60src phosphorylating event.

Karyotype analysis and quantitation of viral transforming genes in Rous sarcoma virus transformed, revertant, and retransformed field vole cells.

Comparative studies of the number of cellular chromosomes and viral genes, including the gene required for malignant transformation, were performed on several clones of Rous sarcoma virus-transformed, revertant, and spontaneously retransformed field vole cells. The results of these studies indicate that no appreciable differences in either total viral gene equivalents or transforming gene sequences can be detected between transformed and revertant cell types, even though considerable differences in the number of certain chromosomes exist among the clones tested. Furthermore, no increase in the amount of total genes or transforming gene sequences accompanies retransformation of revertant clones, including clones that exhibited significant increases in chromosome number following retransformation.