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J P Rousset

Publications and source records attributed to J P Rousset.

25 records · Page 2Linked to original sources
PubMed1979

Phenotype and surface antigens of mouse teratocarcinoma x fibroblast cell hybrids.

Numerous colonies of hybrids between PCC4-aza 1 teratocarcinoma cells and fibroblasts of the heteroploid Cl.1D cell line were examined. All of the hybrids were fibroblasts showing extinction of the multiple developmental potentialities of the teratocarcinoma cell parent, irrespective of whether the teratocarcinoma parent was diploid or tetraploid. The hybrids did not show loss of any specific chromosome contributed by the PCC4-aza 1 cell parent. In contrast with the PCC4 parental cells which carry F9 antigens and do not express H-2b, the hybrids do not express F9 antigens and carry H-2 alloantigens of both parental specificities. These results suggest that in hybrids whose phenotype is that of the Cl.1D parent, a change may occur in the genetic program of the teratocarcinoma cells.

Animals↗
PubMed1979

Presence and cell growth-related variations of glycogen in human colorectal adenocarcinoma cell lines in culture.

The presence and kinetics of intracellular glycogen levels were studied, in relationship to cell growth, in asynchronous and in synchronized cultures of four human colorectal adenocarcinoma cell lines (HT-29, HRT-18, SW-480, and Caco-2). The results show that a specific pattern of glycogen accumulation occurs during the process of cell growth of the studied cell lines. The kinetics of glycogen accumulation in asynchronous cultures were similar from one cell line to another and were characterized by a low amount in the exponential phase of growth, followed by a 3- to 4-fold increase in the stationary phase. The quantities found in either phase were specific for each cell line. The maximum values found in Caco-2, HRT-18, HT-29, and SW-480 cells were, respectively, 258.5 +/- 6.9 (S.D.), 88.9 +/- 2.6, 87.5 +/- 3, and 17.5 +/- 1.8 microgram of glycogen per mg of proteins. The kinetics of glycogen accumulation during the cell cycle was also studied in synchronized cultures of HT-29 and HRT-18 cell lines. Both cell lines exhibited a common pattern of low glycogen quantities during S, G2, and M followed by an increase beginning with G1 and peaking (2.5 to 3 times the initial values) in the middle of this phase. This was followed by a symmetrical decrease in the second half of G1.

Adenocarcinoma↗
PubMed1977

Tumor x host cell hybrids in the mouse: chromosomes from the normal cell parent maintained in malignant hybrid tumors.

We investigated whether the malignancy of hybrids between normal and malignant cells could be correlated with the loss of specific genes borne by specific chromosomes from the normal parent cells. Tumors produced in mice by the inoculation of Cl.1D cells (an L cell derivative) contained tumor x host cell hybrids. Hybrid cell populations isolated from 14 tumors were injected into 123 mice, of which 108 (87%) developed tumors. Metaphases of growing hybrid cell tumors were analyzed by use of a trypsin-Giemsa banding technique. The chromosomes contributed by the host (normal) parent cell could be distinguished from Cl.1D chromosomes, since the latter exhibited morphologic differences due to rearrangements. In the 14 hybrid tumors analyzed, we found that any one of the chromosomes of the host cell might be present, which indicated that none of the chromosomes from the normal cell bore genetic information capable of suppressing the malignancy of Cl.1D cells. Absence of complimentation in the hybrids suggested that, even if the accumulation of several mutations were necessary for malignant tumor growth of Cl.D1 cells, none of these mutations is recessive.

Animals↗
PubMedDate not supplied

Expression vectors for quantitating in vivo translational ambiguity: their potential use to analyse frameshifting at the HIV gag-pol junction.

Translational errors are necessary so as to allow gene expression in various organisms. In retroviruses, synthesis of pol gene products necessitates either readthrough of a stop codon or frameshifting. Here we present an experimental system that permits quantification of translational errors in vivo. It consists of a family of expression vectors carrying different mutated versions of the luc gene as reporter. Mutations include both an in-frame stop codon and 1-base-pair deletions that require readthrough or frameshift, respectively, to give rise to an active product. This system is sensitive enough to detect background errors in mammalian cells. In addition, one of the vectors contains two unique cloning sites that make it possible to insert any sequence of interest. This latter vector was used to analyse the effect of a DNA fragment, proposed to be the target of high level slippage at the gag-pol junction of HIV. The effect of paromomycin and kasugamycin, two antibiotics known to influence translational ambiguity, was also tested in cultured cells. The results indicate that paromomycin diversely affects readthrough and frameshifting, while kasugamycin had no effect. This family of vectors can be used to analyse the influence of structural and external factors on translational ambiguity in both mammalian cells and bacteria.

Amino Acid Sequence↗
PubMedDate not supplied

A subfamily of E. coli palindromic units implicated in transcription termination?

We previously described a family of dispersed palindromic sequences highly repeated in Escherichia coli and Salmonella typhimurium genomes. These sequences, called PU (palindromic units), are located outside structural genes. Conflicting results have been reported on the effects of different PU in transcription termination. Two PU located between co-transcribed genes in S. typhimurium were found not to cause transcription termination [25]. One PU located between convergently transcribed genes in E. coli behaved as bidirectional transcription terminators [12]. In the present paper, we show that three PU located between co-transcribed genes in E. coli are not a transcription terminator. From the literature, we define a subfamily of PU, which we called PU, located between convergently transcribed genes which we implicate in bidirectional transcription termination. This plus the analysis of another PU which terminates transcription suggest that pecularities in the sequence or in the sequence environment of PU determine their role in transcription termination.

Escherichia coli↗