Are there human analogs of the mouse T locus in central nervous system malformations?
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to F Jacob.
Explore the source record for details and available documents.
The expression of the H-Y antigen has been tested on several human lymphoid lines and mouse teratocarcinoma cell lines during differentiation. The human male lymphoid cell line Raji is a very useful target for studies of the H-Y antigen by lymphocytotoxicity test with rat anti-H-Y sera. With a few exceptions, all cells carrying the Y chromosome were H-Y positive. One of the exceptions is the human Daudi cell line which, besides lacking H-Y antigen, also lacks beta2-microglobulin. We have studied a possible association between the H-Y antigen, beta2-microglobulin, and HLA antigen with redistribution experiments. The results strongly suggest that H-Y antigen is not associated with HLA antigens but with beta2-microglobulin.
Explore the source record for details and available documents.
The base-sequence complexities and relative abundance of polysomal and nuclear polyadenylated [poly(A+)] RNA sequences have been analyzed in a pluripotent embryonal carcinoma cell line. Polysomal RNA and nuclear poly(A+) RNA have a complexity representing respectively 0.5% and 2.5% of the single copy component of haploid mouse DNA (1.8 X 10(6) K base pairs). By hybridization with specific cDNAs, three abundance classes were found in polysomal poly(A+) RNA, representing respectively 31%, 33%, and 36% of the RNA, with base sequence complexities of 0.1 X 10(3), 0.9 X 10(3), and 14.5 X 10(3) kilobases. This corresponds to 7000-8000 different mRNA species of an average length of 2000 nucleotides, present on an average of 5 to 600 copies per cell. In nuclear RNA, a major class of abundance was found with a complexity of 100 X 10(3) kilobases, each sequence being present in 1 copy per nucleus. The majority of the polysomal poly(A+) RNA sequences are represented in the nuclear poly(A+) RNA but are present in a more restricted range of relative abundance implying posttranscriptional mechanisms of quantitative modulation: polysomal RNA sequences appear to be preferentially transcribed into nuclear cDNA suggesting a preferential location of these sequences close to poly(A) sequences. The presence of a specialized gene product, globin specific RNA, could not be detected either in the nuclear or polysomal compartments of embryonal carcinoma cells, even at levels that would have detected one sequence per 50 cells.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
From embryonal carcinoma cells labeled with fucose, two main classes of glycopeptide products of Pronase digestion can be distinguished by Sephadex G-50 column chromatography: one eluted near the excluded volume and a smaller one. The large fucosyl-glycopeptides are scarcely present in differentiated cells derived from embryonal carcinoma cells (i.e., fibroblastlike cells, myoblasts, and parietal yolk-sac carcinoma). During in vitro differentiation of embryonal carcinoma cells, these large glycopeptides disappear almost completely. The small glycopeptides were analyzed by paper electrophoresis, concanavalin A-Sepharose affinity chromatography, and digestion with an endoglycosidase. The major components of these glycopeptides from embryonal carcinoma cells appear to be different from complex glycopeptides known to occur in adult cells. The glycopeptide pattern of mouse preimplantation embryos resembles that of embryonal carcinoma cells. These results suggest that the carbohydrate profile changes fundamentally during early stages of mammalian development.
Metabolic cooperation has been used as an index of intercellular communication between mouse embryonal carcinoma (EC) and other cell types. EC cells do not cooperate with differentiated cells of various properties or origins. In contrast they cooperate with cells of all other EC lines tested, including a human teratocarcinoma line, but with different efficiencies. This might reflect differences either in cell-cell interactions or in the formation of gap junctions. During in vitro differentiation, EC cells appear to remain isolated from differentiated cell types.
A rabbit antiserum raised against papain-solubilized H-2 antigens has been used to investigate the eventual expression of H-2 antigens and related molecules on embryonal carcinoma cells and on other types of mouse cells. No material reacting with this serum could be detected on cells carrying the F9 antigen. It is concluded that no H-2 antigen or cross-reacting material is expressed on these cell types.
HMBA induces differentiation in the whole population of some multipotential embryonic carcinoma cells. Morphological, biochemical and immunological changes can be observed even after short treatment. The cells lose the embryonal F9 antigen without acquiring H-2 antigens.
The fate of F9, a surface antigen common to embryonal carcinoma cells and cleavage embryos, as well as to male germ line cells has been studied in post-implantation mouse embryos. The antigen is readily detected on the surface of 7-day and 8-day, but not on 9-day embryonic cells, using anti-F9 serum absorption experiments and indirect immunofluorescence staining. In addition, it is shown that an anti-F9 serum absorbed with 8-day (but not with 9-day) embryonic cells does not react with cleavage embryos (morulae). It is concluded that the antigenic determinants, which are recognized on the surface of morulae by the anti-F9 serum, persist until day 8 of embryogenesis, but are not detected on day 9, either due to their absence, masking or quantitative reduction.
Explore the source record for details and available documents.
A 7-year-old male presented with apparently banal but repetitive episodes of paroxysmal supraventricular tachycardia, along with other manifestations of atrial hyperexcitability. Isolated dilatation of the right atrium was discovered. This disorder is usually latent or benign, but sometimes it is serious because of conduction defects. Lack of relevant studies means the basis of the disorder is not understood.
Fab fragments of a Rabbit anti-F 9 serum do not disturb cleavage of Mouse embryos in culture but prevent blastocyst formation. This effect is reversible for a few hours. It is observed neither with Fab fragments directed against another surface antigen of blastomers nor with monovalent concanavalin A.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.