Biomedical subjects

C Babinet

Publications and source records attributed to C Babinet.

129 records · Page 8Linked to original sources

PubMedDate not supplied

The human desmin gene: a specific regulatory programme in skeletal muscle both in vitro and in transgenic mice.

Desmin synthesis is restricted to cardiac, skeletal and smooth muscles. In several familial myopathies involving fibre disorganization, filamentous aggregation of desmin has been characterized. During the development of the mouse embryo, desmin is one of the first muscle proteins detected in both the heart and the somites. To identify the DNA sequences involved in the regulation of desmin gene expression a 4.5 kb 5'-flanking region of the human desmin gene has been isolated. Different mutants were used to characterize specific enhancers in vitro and in vivo. The results obtained with transgenic mice provide evidence that the 1 kb cis-regulatory sequences, functional in skeletal muscle cells in vitro, confer specific developmental control for skeletal muscles. Furthermore, distinct programmes for cardiac and skeletal muscle-specific expression of the desmin gene are revealed.

Animals↗

PubMedDate not supplied

Heat shock proteins, first major products of zygotic gene activity in mouse embryo.

In many species, the early post-fertilization development of the egg appears to occur mainly under maternal control and does not require transcription of the embryonic genome. In the mouse this situation is restricted to the one-cell stage; activation of the embryonic genome occurs at the late two-cell stage and results in a drastic change in the spectrum of proteins synthesized. This activation is preceded by a decrease in the overall synthesis of proteins at the end of the one-cell stage and the appearance, at the early two-cell stage, of a set of new polypeptides of molecular weight approximately 70,000 (70K) (refs 2, 8, 9). This can be compared with the series of events that occur after hyperthermia in differentiated cells. Heat shock results in an arrest of most transcription and translation; subsequently, expression of a limited set of genes, the heat shock genes, precedes the overall reactivation of cellular genome. Here we show that the 70K early two-cell-specific proteins are identical to two of the mouse heat shock proteins, HSP 68 and HSP 70.

Animals↗

PubMedDate not supplied

Immunoglobulin allotypy of allophenic rabbits.

We obtained two allophenic rabbits formed by the manipulation of blastocysts from strains which differed by their coat colour and their immunoglobulin allotypic specificities. The phenotype of these two rabbits was a1,a2,a3,b4. They were chimeras for their lymphocytic system but not for their coat colour as they had the homogeneous brown coat colour of one of their parental strain. The IgG concentration in the serum of these allophenic rabbits was of the same order of magnitude as the IgG concentration in the serum of normal rabbits of the same age. Twenty-five weeks after birth, one of the allophenic rabbits expressed predominantly the a1 allotypic specificity (around 70% a1, 5% a2, 20% a3) which came from its brown parents, while the second one expressed predominantly the a3 allotypic specificity (around 2% a1, 20% a2, 60% a3) which came from its white parents. Each allotypically different IgG produced by these allophenic rabbits possessed the whole set of allotypic determinants found on IgG carrying the same specificity and produced by normal rabbits. We did not find significant signs of genetic information transfers from the cells of one parental strain to the cells of the other parental strain, or of eventual perturbations of the functional haploidy of the immunoglobulin-producing cells. As these allophenic rabbits only had different a series allotypic specificities, the probability of finding such signs was certainly low as they would have implied hybrid IgG molecules with two allotypically different heavy chains. We now have allophenic rabbits in which different a and b series allotypic specificities are involved and with which we will look for hybrid IgG molecules with heavy chains from one parental strain and light chains from the other parental strain. With these two rabbits we observed the "chimeric drift", namely the slow disappearance of constituants (here one allotypic specificity) coming from one parental strain. The first progeny tests carried out with these allophenic rabbits indicated that they did not seem to be chimeras at the germinal cell level. All their first offspring which were homogeneously brown and homozygous a1,b4 expressed the whole set of variants and determinants of the a1 or the b4 allotypic specificity.

Animals↗