Expression of A- and C-Type Particles in Early Mouse Embryos

Chase, David; Pikó, Lajos

doi:10.1093/jnci/51.6.1971

Cited by 120 publications

(43 citation statements)

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“…Although A-particles are quite abundant in preimplantation mouse embryos (7,8,13) and in certain mouse tumor cells (30), we have no idea of the fraction of transcriptionally active genes in these situations or whether any such genes are included among our isolates. A-particles from different tumors contain, in addition to 35S RNA, a variety of smaller but sequence-related RNA species: e.g., a 32S RNA is abundant in particles from neuroblastoma and MOPC-21 myeloma cells, whereas a 29S form predominates in MOPC-104E (36).…”

Section: Discussionmentioning

confidence: 99%

Intracisternal A-particle genes in Mus musculus: a conserved family of retrovirus-like elements.

Kuff¹,

Smith²,

Lueders³

1981

Mol. Cell. Biol.

100

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The structural organization of intracisternal A-particle genes has been studied, using isolates from a mouse gene library in X phage Charon 4A. The predominant gene form among the isolates was 7.3 kilobases (kb) in length. R-loops between the 7-kb (35S) A-particle genomic ribonucleic acid and several of these genes were colinear, with no visible evidence of intervening deoxyribonucleic acid sequences. One recombinant was found with an A-particle gene that contained a 1.7-kb deletion. Using the deletion as a reference, the deoxyribonucleic acid and ribonucleic acid homology regions were localized with respect to one another and to the restriction map: the 5' terminus of the ribonucleic acid was several hundred base pairs within the 5' end of the deoxyribonucleic acid homology region. Restriction endonuclease fragments encompassing the 5' and 3' regions of one 7.3-kb gene were separately subcloned into pBR322. Heteroduplexes between the two subclones revealed an approximately 300-base pair segment of terminally redundant sequences. The cloned 3' fragment hybridized with restriction fragments from the 5' end of several other A-particle genes, demonstrating the presence of common (though not necessarily identical) terminally repeated sequences. A-particle genes varied in the occurrence of specific restriction sites at characteristic internal loci. However, heteroduplexes between several variant 7.3-kb genes showed continuous homology regions even when spread under stringent hybridization conditions. The relative abundance of restriction site variants was highly conserved in 12 laboratory strains of Mus musculus, in embryonic and adult tissues of a single inbred strain, and in the SC-1 cell line of feral mouse origin, but appeared to differ in a feral Japanese substrain, Mus musculus molossinus. Some evidence suggests that subsets of A-particle genes may have similar flanking sequences. The results are discussed in terms of the evolution of this multigene family.

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Section: Discussionmentioning

confidence: 99%

Intracisternal A-particle genes in Mus musculus: a conserved family of retrovirus-like elements.

Kuff¹,

Smith²,

Lueders³

1981

Mol. Cell. Biol.

100

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“…After a minimum at the two-to four-cell stage, there is some increase in this type of IAP with further development, but the numbers remain small in the embryos of most of the mouse strains examined. (A second population of morphologically distinct intracisternal particles, the "small IAPs" [6] or "£-particles" [46], shows a reciprocal time course of appearance, reaching a peak of abundance at the two-cell state and diminishing thereafter. At all periods after cleavage begins, the e-particles far outnumber the larger IAPs.…”

Section: Methodsmentioning

confidence: 99%

Intracisternal A-particle gene expression in normal mouse thymus tissue: gene products and strain-related variability.

Kuff¹,

Fewell²

1985

Mol. Cell. Biol.

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Intracisternal A-particle (IAP)-specific sequences were 5-to 10-fold enriched in polyadenylated RNA from BALB/cJ thymus as compared with RNAs from liver, spleen, and kidney. The major transcripts of 7.2 and 5.4 kilobases were the same size as those found in an TAP-rich neuroblastoma cell line. The absolute levels and proportions of these transcripts varied in thymuses from mice of different inbred strains. With antiserum prepared against p73, the main IAP structural protein, several size classes of IAP-related proteins were immunoprecipitated from extracts of thymus cells incubated with [35S]methionine; these included p73 itself and a group of polypeptides in the size range of 114 to 120 kilodaltons (pll4-pl20). The inbred strains showed marked characteristic differences in the electrophoretic patterns of their IAP-related proteins. Earlier studies showed that the 7.2-kilobase RNA from neuroblastoma IAPs coded for p73 in a cell-free translation system. Correlations between the RNA and protein patterns in thymuses of the different inbred strains indicated that 5.4-kilobase RNA gives rise to the pll4-pl20 polypeptides. Metabolically labeled p120 was found to include methionine-containing tryptic peptides of p73 plus additional peptides consistent with its larger size. In vivo labeling kinetics showed that the pll4-pl20 polypeptides were not major precursors of p73 in intact neuroblastoma cells. This study shows that IAP gene expression in mouse thymus is genetically determined and that a novel class of IAP-related polypeptides can be expressed independently of the major particle structural protein.Intracisternal A-particles (IAPs) are retrovirus-like entities found in many types of mouse tumor cells (20,45). They contain a group-specific internal structural protein, p73 (20,32), and a DNA polymerase activity with properties of reverse transcriptase (42, 43). The isolated particles also contain specific polyadenylated [poly(A)] RNAs (30) ranging in size from 7.2 to about 3.5 kilobases (kb) (34,36,41). These RNA species, which are related to one another in sequence, vary in relative proportion in particles isolated from different tumor sources. Endogenous provirus-like elements homologous to the IAP-associated RNAs ("IAP genes") are reiterated 1,000-fold per haploid genome in Mus musculus (28). The full-size genetic unit is 7.3 kb in length and is colinear with the 7.2-kb transcript (21). Shorter elements with internal deletions are also found (21, 34), and one group of these, the so-called type IT elements (40), are known to give rise to some of the shorter IAP-specific RNAs (34, 41). The IAP genetic elements share many structural properties with integrated retroviral proviruses and certain transposable elements in Drosophila spp. and yeasts (8a). Recently, IAP genes have been found to appear in novel locations in the genome of certain IAP-rich BALB/c mouse myeloma and hybridoma cell lines and to affect the function of genes at the various target sites (5,7,9,10,18,19,41). Thus, on occasion they can act as mobile e...

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“…No MCMV-specific fluorescence was observed in any of the embryos obtained from infected or uninfected mice on Days 2, 3 and 4 of pregnancy, but several virus-like particles were seen in a few blastomeres of embryos recovered on Day 4 of pregnancy from infected mice. The particles were budding from the nuclear membrane or contained in cytoplasmic vesicles: they were distinct from the endogenous A-and C-type particles found in mouse preimplantation embryos (Chase & Pikó, 1973) and were of similar size and morphology to the intracellular MCMV particles observed in MCMV-infected hepatic parenchymal cells (Reubner, Miyai, Slusser, Wedemeyer & Medearis, 1964). However, none of the embryonic blastomeres examined exhibited the acute productive infection typical of MCMVinfected somatic cells.…”

Section: -77mentioning

confidence: 83%

“…A direct interaction between viruses and the preimplantation embryo could affect subsequent development. For example, A-and C-type oncovirus particles, identical to those found in certain neoplastic tissues, have been found in oocytes and preimplantation embryos of mice (Chase & Pikó, 1973), guinea-pigs (Enders & Schlafke, 1965 ; Andersen & Jeppesen, 1972) and primates (Kalter et al, 1974a, b), and their presence may be related to the development of neoplasia in later life (Biczysko, Pienkowski, Solter & Koprowski, 1973a). The viruses which cause murine leukaemia and mammary tumours in certain mouse strains are known to be transmitted vertically via the egg and early embryo (Zeilmaker, 1969;Bentvelzen, Daams, Hageman & Calafat, 1970;Gross, 1970).…”

Section: Introductionmentioning

confidence: 99%

Studies on the susceptibility of the mouse preimplantation embryo to infection with cytomegalovirus

Neighbour¹

1978

Reproduction

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Expression of A- and C-Type Particles in Early Mouse Embryos

Cited by 120 publications

References 0 publications

Intracisternal A-particle genes in Mus musculus: a conserved family of retrovirus-like elements.

Intracisternal A-particle genes in Mus musculus: a conserved family of retrovirus-like elements.

Intracisternal A-particle gene expression in normal mouse thymus tissue: gene products and strain-related variability.

Studies on the susceptibility of the mouse preimplantation embryo to infection with cytomegalovirus

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