Biomaterial Database

Suppression of the progression phenotype in somatic cell hybrids occurs in the absence of altered adenovirus type 5 gene expression. 1990

G J Duigou, and L E Babiss, and D S Iman, and J W Shay, and P B Fisher

Department of Neurological Surgery, Columbia University, College of Physicians and Surgeons, New York, New York 10032.

In the present study we have analyzed the genetic regulation of increased expression of transformation-associated traits, a process termed progression, in adenovirus type 5 (Ad5)-transformed secondary rat embryo cells. Somatic cell hybrids were formed between a highly progressed neomycin-resistant Ad5-transformed cloned cell line (E11-NMTneo) and an untransformed chloramphenicol-resistant rat embryo fibroblast cell line (CREFcap). Parental E11-NMTneo cells grew with high efficiency in agar, exhibited reduced 125I-epidermal growth factor (EGF) binding, and were tumorigenic in nude mice. Parental CREFcap cells exhibited phenotypes opposite to those of E11-NMTneo cells. A high proportion (84%) of the presumptive hybrid cell types obtained after fusion and genetic selection (G418 and chloramphenicol) displayed a flat morphological phenotype intermediate between CREFcap and E11-NMTneo cells, suggesting that a trans-dominant extinction phenomenon had occurred. Two hybrids with a round morphology (R), which still exhibited the progressed phenotype, and two hybrids with a flat morphology (F), which had lost the progressed phenotype, were chosen for detailed analysis. Both R hybrids grew efficiently in agar, exhibited low 125I-EGF binding, and were tumorigenic in nude mice, whereas both F hybrids grew poorly in agar, displayed increased 125I-EGF binding in comparison with E11-NMTneo and R hybrids, and were nontumorigenic in nude mice. An analysis of the viral DNA integration patterns and the rates of transcription, steady-state mRNA accumulation, and relative levels of the Ad5 E1A and E1B gene products revealed no differences among the parental and hybrid cells. These studies indicate that normal CREF cells may contain a suppressor gene(s) which can inhibit the expression of specific traits of the progression phenotype in Ad5-transformed cells and that this suppression is not associated with changes in the expression of Ad5 transforming genes.

UI	MeSH Term	Description	Entries
D009856	Oncogene Proteins, Viral	Products of viral oncogenes, most commonly retroviral oncogenes. They usually have transforming and often protein kinase activities.	Viral Oncogene Proteins,Viral Transforming Proteins,v-onc Proteins,Transforming Proteins, Viral,v onc Proteins
D002472	Cell Transformation, Viral	An inheritable change in cells manifested by changes in cell division and growth and alterations in cell surface properties. It is induced by infection with a transforming virus.	Transformation, Viral Cell,Viral Cell Transformation,Cell Transformations, Viral,Transformations, Viral Cell,Viral Cell Transformations
D004279	DNA, Viral	Deoxyribonucleic acid that makes up the genetic material of viruses.	Viral DNA
D005786	Gene Expression Regulation	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.	Gene Action Regulation,Regulation of Gene Expression,Expression Regulation, Gene,Regulation, Gene Action,Regulation, Gene Expression
D005814	Genes, Viral	The functional hereditary units of VIRUSES.	Viral Genes,Gene, Viral,Viral Gene
D006822	Hybrid Cells	Any cell, other than a ZYGOTE, that contains elements (such as NUCLEI and CYTOPLASM) from two or more different cells, usually produced by artificial CELL FUSION.	Somatic Cell Hybrids,Cell Hybrid, Somatic,Cell Hybrids, Somatic,Cell, Hybrid,Cells, Hybrid,Hybrid Cell,Hybrid, Somatic Cell,Hybrids, Somatic Cell,Somatic Cell Hybrid
D000256	Adenoviridae	A family of non-enveloped viruses infecting mammals (MASTADENOVIRUS) and birds (AVIADENOVIRUS) or both (ATADENOVIRUS). Infections may be asymptomatic or result in a variety of diseases.	Adenoviruses,Ichtadenovirus,Adenovirus,Ichtadenoviruses
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013489	Suppression, Genetic	Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).	Suppressor Mutation,Genetic Suppression,Genetic Suppressions,Mutation, Suppressor,Mutations, Suppressor,Suppressions, Genetic,Suppressor Mutations
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription