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C Salomon

Publications and source records attributed to C Salomon.

6 recordsLinked to original sources
PubMed1992

Fibronectin gene expression in proliferating, quiescent, and SV40-infected mouse kidney cells.

To study alterations in cellular gene expression in mouse kidney cell cultures infected with simian virus 40 (SV40) or polyomavirus, we performed a differential screening of a mouse kidney cDNA library with probes prepared from mRNAs of virus-infected and mock-infected cells. We isolated and characterized cDNA recombinant pKT13 which detected increased mRNA levels in infected cells. Sequence analysis of pKT13 revealed close to 100% homology with the 3'-end of mouse fibronectin (FN) mRNA. Since primary cultures of baby mouse kidney cells have been extensively characterized in our laboratories, we studied FN gene expression at different stages of uninfected and virus-infected cultures. High levels of FN and of its mRNA were found in the kidneys of suckling mice, while in primary cultures of proliferating epithelial kidney cells the expression of FN was very low until the cultures became confluent. Thereafter FN increased and reached high levels in cells which were irreversibly arrested in phase Go and which had apparently exhausted their finite division potential. Infection of confluent cultures with polyomavirus or SV40 resulted in a further stimulation of FN gene expression. However, during abortive infection with SV40, FN mRNA and FN levels decreased with emergence of transformed cells and were low in an established SV40-transformed mouse kidney cell line. These changes in FN gene expression suggest that high levels of FN might be indicative in vivo for terminal differentiation and in vitro for cellular senescence.

Amino Acid Sequence↗
PubMed1977

Polyoma-induced stimulation of cellular RNA synthesis is paralleled by changed expression of the viral genome.

We studied synthesis of viral and cellular RNA in the presence and absence of 5-fluorodeoxyuridine (FdU, an inhibitor of DNA synthesis) during lytic infection with polyoma virus in confluent, primary mouse kidney cell cultures. In the presence of FdU, synthesis of early 19S polyoma mRNA and of polyoma tumor (T)-antigen, i.e. expression of the early viral gene, is rapidly followed by a mitogenic reaction of the host cell; it leads to an increase of 30 +/- 5% in cellular, mainly 28S and 18S rRNA, followed by activation of the cellular DNA-synthesizing apparatus. Polyoma-induced cellular RNA synthesis is paralleled by increased production of early 19S mRNA and begin of expression of the late viral genes, leading to synthesis of small amounts of late 19S and 16S mRNAs. Changed expression of the viral genome occurs in the absence of detectable synthesis of polyoma DNA I. Infection in the absence of FdU induces the same sequence of events; it is followed, however, by duplication of the mouse cell chromatin (S-phase) and production of progeny virus.

Cell Line↗
PubMed1976

Mapping of the three species of polyoma mRNA.

The polyoma mRNA's present in the cytoplasm of primary cultures of mouse kidney cells during lytic infection were characterized by sedimentation velocity analysis and by hybridization to polyoma DNA fragments generated by a specific endonuclease of Hemophilus parainfluenzae (Hpa II).

Base Sequence↗
PubMed1976

Isolation and characterization of poly(A)-containing intranuclear polyoma-specific "giant" RNA'S.

Heterogeneous polyoma giant RNA molecules have been isolated by oligo(dT)- cellulose chromatography during the late phase of a lytic cycle of infection of mouse kidney cell cultures. These RNAs have sedimentation coefficients in denaturing Me2SO gradients that are greater than 26S and thus apparently correspond to RNA molecules larger than one strand of polyoma DNA. Approximately 15% of total nuclear polyoma late giant RNAs contained tracts of poly(A) and were retained by oligo(dT)-cellulose. The polyoma late giant RNAs as well as heterogeneous nuclear RNAs (HnRNAs) were found to have a slightly lower sedimentation rate in Me2SO-chloral hydrate density gradients than sedimentation values in sucrose gradients indicated. Even when synthesis of viral DNA and the production of capsid protein are blocked by 5-fluorodeoxyuridine (FdU), 10% of polyoma-specific RNA (as determined by sedimentation analyses under aqueous conditions) was shown to contain tracts of poly(A). In contrast to our findings on polyoma late giant RNA, nuclear polyoma RNA synthesized in the presence of FdU sedimented in denaturing Me2SO-chloral hydrate gradients considerably slower (from 15 to 30S) in relation to HnRNA and ribosomal precursor RNA. The sedimentation pattern in denaturing Me2SO gradients suggest that Py RNA synthesized late in lytic infection in the presence of FdU may be no longer than one transcript of Py DNA.

Cell Line↗