Isolation and characterization of beta-actin gene of carp (Cyprinus carpio)

A beta-actin gene of carp (Cyprinus carpio) was isolated from a genomic EMBL3 library. The nucleotide sequence of the gene indicates six exons spanning 3.6 kb. Southern blot hybridization of restriction endonuclease digests of carp genomic DNA indicate that there are two copies of the beta-actin isotype and several other species of actin genes. The transcriptional start site is 85 bp and 24 bp downstream respectively from consensus CCAAT and TATA promoter elements. The organization of the carp beta-actin gene is identical to that of chicken, human, and rat genes in terms of size, exon/intron locations and junctions and in having a translationally silent first exon. The fish gene is 90% and 99% conserved at the nucleotide and amino acid levels, respectively, with land vertebrate beta-actin genes. Northern blot analysis of beta-actin gene expression indicated that the gene is highly expressed in brain, less so in muscle, and much less so in liver cells. The putative beta-actin proximal promoter of carp, identified by the conservation of known actin regulatory sequences, is transcriptionally active in both mammalian and piscine cells.

A clinical, histopathologic, and molecular biologic investigation of vulvar intraepithelial neoplasia

The spectrum of vulvar intraepithelial neoplasia (VIN) was investigated with human papillomavirus (HPV) DNA probes by Southern blot hybridization technique. The results of vulvar tissue examinations from 25 patients were compared to prior genital and systemic diseases, clinical presentation, and histopathologic manifestations. The presence of HPV DNA in these lesions was largely associated with multifocality of the lesions, the presence of synchronous and metachronous multicentric genital neoplasia, and depressed immunocompetence. These findings indicate that VIN is associated with HPV and may have an infectious etiology.

Epidermodysplasia verruciformis in a setting of common variable immunodeficiency

A 14-year-old native American female with common variable immunodeficiency was admitted for bone marrow transplantation. Preoperative evaluation showed a generalized lichenoid papular eruption present for several years. Light microscopy revealed expansion of the epidermis by atypical keratinocytes; electron microscopy showed intranuclear papillomavirus inclusions within the granular keratinocytes; DNA hybridization revealed a type 5-related human papilloma virus homology. Four days after bone marrow transplantation the lichenoid papules blackened and began to disappear. Within 30 days after bone marrow transplantation the distribution and appearance of the papules was similar to that of the pretransplantation evaluation. One year after transplantation the patient showed evidence of a successful T lymphocyte graft. No transformation to squamous cell carcinoma had occurred. Epidermodysplasia verruciformis has been associated with deficient cell-mediated immunity, the varying severity of which does not predict the tendency to neoplasm formation (2, 5). Several distinct human papillomavirus genomes have been recovered with DNA hybridization techniques in these patients. It is hoped that the bone marrow transplantation might be associated with diminished transformation to squamous cell carcinoma.

Immunology of human papillomavirus: warts

Great progress has been made over the last five years in our understanding of papillomavirus (PV) biology. New technology has enabled investigators to understand the relationship between the PV and its host. The PV cannot be cultured in vitro, and this has led to limitations for those wishing to study the biology of this virus. However, utilizing recombinant DNA technology, investigators now have abundant quantities of human papillomavirus (HPV) DNA for study. Such HPV genomes may be labeled with a radioisotope such as P32 and used as a "probe" in hybridization studies to see if a given tissue contains HPV DNA. No longer are we limited to electron microscopy and immune studies in our efforts to identify HPV within benign or malignant tissues. Ultimately, we hope to understand the relationship between the virus and its host. This paper will concentrate on one aspect of this relationship--the immunology of HPV.

Characterization of two HPV-3 related papillomaviruses from common warts that are distinct clinically from flat warts or epidermodysplasia verruciformis

We have recently identified two unusual human papillomavirus (HPV) isolates while engaged in an ongoing study of wart disease in meat handlers and veterinarians. The papillomas from which these two viruses were isolated clinically resembled verruca vulgaris rather than either flat warts or epidermodysplasia verruciformis (EV). These two previously uncharacterized HPVs were molecularly cloned and characterized with respect to known HPVs. The genomes of the two viruses exhibited dramatically different restriction endonuclease cleavage patterns but were found to have significant sequence homology to each other, as well as to HPV-3 and a new virus isolated from a patient with EV. Neither of the two new HPV isolates exhibit detectable sequence homology under stringent conditions of hybridization or share similar restriction endonuclease cleavage patterns with previously characterized HPV types 1,2,4,5,6b, or a previously isolated HPV from meat handlers.

Production and characterization of monoclonal antibodies against avian retrovirus reverse transcriptase

Monoclonal antibodies were prepared against the avian myeloblastosis virus reverse transcriptase. These monoclonal antibodies specifically immunoprecipitated the alpha and beta subunits of the reverse transcriptase molecule, as well as the Pr180gag-pol precursor protein present in virus-infected cells. In addition, these monoclonal antibodies inhibited the DNA polymerase activity associated with the reverse transcriptase molecule but not the RNase H activity. The monoclonal antibody preparations were specific for the amino-terminal portion of the protein, as determined by the immunoprecipitation of a reverse transcriptase-beta-galactosidase fusion protein produced in Escherichia coli by molecular cloning procedures.

Inhibition of RNA-dependent DNA polymerase of Rous sarcoma virus by thiosemicarbazones and several cations

The RNA-dependent DNA polymerase of Rous sarcoma virus is inhibited by N-methyl isatin beta-thiosemicarbazone and by thiosemicarbazide, but not by semicarbazide. These inhibitors also inactivate, upon contact with the virion, the transforming ability of Rous sarcoma virus. Sulfhydryl donors, such as 2-mercapto-ethanol, can prevent these effects. The RNA-directed activity of the purified polymerase is inhibited to a greater degree than is the DNA-directed activity. Two cations, Cu(++) and Hg(++), can inhibit RNA-dependent DNA polymerase and inactivate the transforming ability of the virus. Synergism between N-methyl isatin beta-thiosemicarbazone and Cu(++) occurs, since treatment of the virus with a low dose of either N-methyl isatin beta-thiosemicarbazone or Cu(++) has little effect; however, when the two compounds are mixed together, significant inactivation occurs. This observation supports the hypothesis that the antiviral action of thiosemicarbazones is a function of their ability to act as a ligand for metallic ions. Several cations (Ag(+), Co(++), Zn(++), Cd(++), and Ni(++)) significantly inactivate the RNA-dependent DNA polymerase, but have little effect on the transforming ability. In view of this result, the conclusion that the enzyme activity is required for transformation remains open to question.

Deoxyribonucleic acid polymerase of Rous sarcoma virus: studies on the mechanism of double-stranded deoxyribonucleic acid synthesis

The deoxyribonucleic acid (DNA) polymerase of Rous sarcoma virus synthesizes both single- and double-stranded DNA, utilizing the ribonucleic acid (RNA) of the viral genome as the initial template. Results of pulse-chase experiments indicate that the single-stranded DNA serves as unconserved template and precursor for the synthesis of double-stranded DNA. The latter reaction is apparently initiated in association with the viral RNA and may involve a partially double-stranded intermediate form.

Deoxyribonucleic acid polymerase associated with avian tumor viruses: secondary structure of the deoxyribonucleic acid product

The products of the deoxyribonucleic acid (DNA) polymerase associated with Rous sarcoma virus and avian myeloblastosis virus were characterized by correlative analyses with equilibrium centrifugation and stepwise elution from hydroxyapatite. The initial enzymatic product consists of nascent DNA chains which are hydrogen-bonded to 70S viral ribonucleic acid (RNA), whereas the final enzymatic product is double-stranded DNA. Appreciable amounts of free single-stranded DNA were not detected at any point during the course of the enzymatic reaction, but the data in this regard are not decisive. The time course of synthesis of DNA:RNA hybrids and double-stranded DNA has been analyzed. It is concluded that the synthesis of double-stranded DNA is a sequel to and is probably dependent upon the synthesis of DNA:RNA hybrid.