PubMed Health⌕ Search

Biomedical subjects

D Morello

Publications and source records attributed to D Morello.

At least 55 records · Page 3Linked to original sources
PubMed1985

Asynchronous regulation of mouse H-2D and beta-2 microglobulin RNA transcripts.

The major transplantation (or H-2) antigens in the mouse are cell-surface glycoproteins composed of a heavy chain and a light chain, the beta-2 microglobulin (beta 2m). The expression of these proteins is regulated during development. Embryonic cells at early stages of development do not express these proteins. On the other hand, these molecules are present on the surface of all adult somatic cells. We investigated whether the expression of both chains was coordinately regulated. Using specific single-stranded DNA probes in an S1 nuclease analysis, we compared the relative amounts of H-2D and beta 2m transcripts in normal tissues, in transformed cells, and during embryonic development. Our results show that (1) the steady state level of beta 2m transcripts varies from one adult organ to another, while that of H-2D transcripts stays approximately the same; (2) upon transformation, the amount of H-2D-specific mRNA increases drastically, while the beta 2m mRNA level remains constant; (3) whereas the quantity of beta 2m mRNA increases during early development, the amount of H-2D mRNA remains at a very low level. These data suggest that the regulation of H-2D and beta 2m genes are not identical and that their activation during development is not synchronous.

Aging↗
PubMed1985

Expression of the cytokeratin endo A gene during early mouse embryogenesis.

Expression of cytokeratin endo A has been analyzed during mouse blastocyst formation and embryonal carcinoma cell differentiation. To study the regulation of endo A expression, nuclease S1 mapping experiments have been performed on RNA extracted from two-cell to 7.5-day embryos. Low levels of endo A mRNA begin to be detectable in eight-cell embryos. The amount of this mRNA increases at the blastocyst stage, suggesting that endo A expression is regulated at the mRNA level during blastocyst formation. At this stage, in situ hybridization studies show that endo A mRNA is present in the trophectoderm but not in the inner cell mass. In 7.5-day embryos, endo A mRNAs are also detectable in the endoderm layer and in the amnion.

Animals↗
PubMed1985

H-2-restricted cytolysis of L cells doubly transformed with a cloned H-2Kb gene and cloned retroviral DNA.

We report the construction of target cells by the double transformation of mouse L cells with a cloned H-2Kb gene and molecular clones of Akv or Gross murine leukemia virus (MuLV) or the cloned gag gene of Akv MuLV. Cytolytic T lymphocytes (CTL) generated in BALB.B mice specific for Gross MuLV (closely related to Akv MuLV) kill these doubly transformed cells. This is a direct indication that a CTL subpopulation recognizes H-2Kb antigen in association with a viral antigen encoded by the gag gene of Gross MuLV.

AKR murine leukemia virus↗
PubMed1984

Functional expression of a mouse H-2Kb gene isolated from non-expressing teratocarcinoma cells.

Embryonal carcinoma cells do not express H-2 antigens or beta 2-microglobulin. Recent studies have suggested that the expression of these antigens is likely to be controlled at the level of transcription. To study the precise organization of the corresponding genes and their possible expression in adult mouse cells, we have isolated H-2-related genes from a genomic cosmid library constructed with PCC4-aza-RI from DNA of EC cells. Clones isolated from the library after stringent hybridization with an H-2 cDNA probe were tested for their ability to direct H-2 antigen synthesis after DNA-mediated gene transfer in a fibroblastic L cell. Four clones have been found to code for the major transplantation antigen H-2Kb. Structural analysis showed that these clones contained the same entire H-2Kb gene, identical to the corresponding gene isolated from differentiated C57Bl/10 cells. Furthermore, the present studies showed that this embryonal carcinoma gene was expressed and was functional when transfected into a differentiated cell.

Animals↗
PubMed1984

Growth conditions of F9 embryonal carcinoma cells affect the degree of DNA methylation.

We have investigated differences in C pG methylation between F9 embryonal carcinoma cells in vitro and as tumor cells grown in vivo using Msp I and Hpa II restriction isoschizomers. Southerns were hybridized with two low copy number probes, mouse major beta-globin (f7) and a class I, histocompatibility-2 cDNA clone (pH-2d-4). In each case, the tumor-DNA was hypomethylated while the DNA from F9 cells grown in vitro was moderately methylated. We conclude that growth conditions or cell-cell interactions can greatly affect methylation of C pG sites.

5-Methylcytosine↗
PubMed1983

Structure and expression of the mouse beta 2-microglobulin gene isolated from somatic and non-expressing teratocarcinoma cells.

Mouse teratocarcinoma cells express neither H-2 heavy chains nor beta 2-microglobulin (beta 2-m). We have constructed two genomic libraries, one from PCC4-aza-RI embryonal carcinoma cells and the other from their adult syngenic counterpart 129/Sv liver cells (H-2bc). The libraries were screened with a full length mouse beta 2-m cDNA probe which we isolated and sequenced. Two cosmid clones carrying the entire beta 2-m gene were isolated, one from each library. There was no detectable difference in structure between the two genes. Furthermore, both were shown to be active and to restore beta 2-m synthesis upon transfer into mutant cells deficient in beta 2-m. Irreversible DNA alterations in or around the beta 2-m gene are thus unlikely to account for the lack of beta 2-m gene expression in embryonal teratocarcinoma cells.

Animals↗
PubMed1980

Serological identification and cellular distribution of three F9 antigen components.

Using an affinity chromatography technique, IgM, IgG1, IgG2a,b anti-F9 antibodies have been isolated from the anti-F9 serum; their activities have been analyzed by IF test on a variety of cell types, teratocarcinoma-derived cell lines, and embryos. The anti-F9 antibodies react with at least three independent antigenic determinants not expressed on the same cell types, and that appear along different time-course during embryonic development.

Animals↗
PubMed1980

A cell surface glycoprotein involved in the compaction of embryonal carcinoma cells and cleavage stage embryos.

Fab fragments of rabbit anti-embryonal carcinoma cells IgG dramatically perturb cell-cell interactions between embryonal carcinoma cells and between early mouse embryo blastomeres. These antibodies prevent compaction of preimplantation embryos (or trigger their decompaction) and have similar effects on embryonal carcinoma cells. They probably act through the masking of specific molecules (Fab targets) involved in the mechanisms of recognition between cells during compaction. Fab target molecules have been extracted from embryonal carcinoma cell membranes and purified using their property to inhibit the effects mediated by anti-embryonal carcinoma Fab. The solubilization of the Fab targets could be achieved using both detergent extraction and trypsin treatment of membranes. In the latter case, a glycoprotein of 84,000 daltons could be purified which has all the properties expected from the Fab target and accounts for most of the Fab-inhibiting activity of embryonal carcinoma cell membranes.

Animals↗
PubMed1979

Antibody response to embryonal carcinoma cells in syngeneic mice.

The immunoglobulin (Ig) classes and subclasses of the specific antibodies contained in antisera raised in male 129/Sv mice against cells of a syngeneic clonal line of embryonal carcinoma (F9) have been determined. Cytotoxic activity was found associated almost exclusively with anti-F9 IgM (micro kappa) antibodies. A large part of anti-F9 activity was found associated with IgG1 (gamma 1 kappa and presumably also gamma 1 lambda) antibodies, and was detectable only by direct immunofluorescence. Traces of specific IgG2a and IgG2b antibodies were also found. No IgG3 and IgA antibodies reacting with embryonal carcinoma cells were detectable under these conditions. The serum of F9 tumor-bearing animals had a very similar Ig composition. Furthermore, IgM and IgG1, but not IgG2 antibodies, were detected at the surface of in vivo growing F9 tumor cells.

Animals↗
PubMed1978

Absence of reaction of a xenogenic anti-H-2 serum with mouse embryonal carcinoma cells.

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.

Animals↗
PubMed1977

The private specificity H-2.4 and the public specificity H-2.28 of the D region are expressed on two independent polypeptide chains.

The antigenic specificities H-2.4 (private) and H-2.28 (public) in the H-2a haplotype are controlled by the D region of H-2 as defined by the available recombinants. In previous studies we have demonstrated by the antibody-induced redistribution method that the antisera against these specificities contain antibodies against at least two different polypeptide chains. We here report the results of the indirect immunoprecipitation of radiolabeled antigens after solubilization with Nonidet-P40. The antisera against the two specificities precipitated from such extracts two different and independent polypeptide chains, indicating that the products of the D region, as presently defined, comprise at least two different molecules. The molecular weight of both chains is approximately 45 000, which is similar to other molecules bearing private H-2 antigenic specificities. Consequently, the chromosomal segment presently defined by recombination studies as the D region, must contain another locus, controlling the second polypeptide chain which is detectable by anti-H-2.28 antisera, besides the H-2D locus which controls the polypeptide chain bearing the private specificity H-2.4 as well as most of the public specificities.

Animals↗