Intracisternal A particles: RNA expression and DNA methylation in murine teratocarcinoma cell lines

De, Fan; Dianoux, Laurent; Périès, J.; Emanoil-Ravicovitch, R

doi:10.1128/jvi.46.1.307-310.1983

Cited by 34 publications

(10 citation statements)

References 16 publications

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“…Intracisternal A particles (IAPs) are endogenous retrovirus-like structures that are found budding from the endoplasmic reticulum in normal mouse preimplantation embryos (1)(2)(3) and in many mouse tumors (14,5), but rarely in normal mouse cells (6). In Mus musculus there are approximately 1000 integrated copies of IAP genes per haploid genome, which represents 0.2% of the total DNA in mouse (7,8).…”

Section: Introductionmentioning

confidence: 99%

“…On the C) I RL Press Umited, Oxford, England. Volume 13 Number 1 1985 289 Nucleic Acids Research Nucleic Acids Research other hand, IAP transcripts from neuroblastomas are 7.2 and 5.3 kb in length (13), while the major species of IAP transcripts in embryonic teratocarcinomas is 5.3 kb (14). This 5.3 kb species is also the major IAP transcript expressed in preimplantation embryos (15).…”

Section: Introductionmentioning

confidence: 99%

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Nucleotide sequences of murine intracisternal A-particle gene LTRs have extensive variability within the R region

et al. 1985

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Nucleotide sequences of the long terminal repeats (LTRs) of four murine intracisternal A-particle (IAP) genes IAP62, 19, 81 and 14 were determined. Each IAP LTR contains three sequence domains, 5'-U3-R-U5-3', and each is bound by 4 bp imperfect inverted repeats. The transcriptional regulatory sequences, CAAT and TATA, as well as the enhancer core sequence GTGGTAA are conserved and precisely positioned within the U3 region. In the R region, the sequence AATAAA is located twenty base pairs preceding the dinucleotide CA, the polyadenylation site. In IAP19 and IAP81, the 5' and 3' LTRs are flanked by a six nucleotide direct repeat of cellular sequences representing the possible integration sites for these IAP proviruses. Both the size and sequences of different IAP LTRs vary considerably, with the majority of the variation localized within the R regions. The size of R varies from 66 bp in IAP14 to 222 bp in IAP62; in contrast, the U3 and U5 regions are all similar in size. These extra sequences within the R region of large LTRs consist of several unusual directly repeating sequences which account for this variability.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nucleotide sequences of murine intracisternal A-particle gene LTRs have extensive variability within the R region

et al. 1985

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“…In addition, IAP expression is induced when teratocarcinoma cells are stimulated to differentiate with retinoic acid (18). In the majority of cells and tissues which have been examined, the IAP transcripts seem to be derived only from very few proviruses (13, 16,18,40). The cellular mechanisms underlying the specificity of IAP expression are unclear.…”

mentioning

confidence: 99%

Expression of intracisternal A-type particles is increased when a B-cell lymphoma differentiates into an immunoglobulin-secreting cell

Wiest¹,

Burkhardt²,

Stockdale³

et al. 1989

J Virol

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The murine B-cell lymphoma CH12, like many other murine cells, expresses intracisternal A-type particles (TAPs). When CH12 cells are treated with lipopolysaccharide, the cells differentiate and secrete immunoglobulin M. The expression of IAP genes was also increased, in parallel with the increased expression of immunoglobulin genes. The amount of IAP mRNA increased within 48 h of lipopolysaccharide treatment and reached a level fivefold higher than that in unactivated CH12 cells. The two major IAP transcripts (7.2 and 5.4 kilobases) were induced to similar extents. The increased level of mRNA was reflected in higher levels of the major IAP structural protein p70, whose abundance increased 3.6-fold. The number of IAP particles per cell also increased upon activation of CH12, from 67 in nonsecreting CH12 to 290 in secreting cells. All of the IAPs were confined to the cisternae of the endoplasmic reticulum (ER), regardless of the differentiation state of the cell. Accompanying the induction of p70 was the induction of the related IAP polypeptide p102. A third viral polypeptide, p120, was also made in CH12; its abundance was almost unchanged. Localization of the IAP proteins on ultrathin frozen sections showed that most were assembled into particles in the ER. However, there were small pools of unassembled proteins both in the ER and on the plasma membrane. p70 and p120 could be detected, by iodination, on the surfaces of both secreting and nonsecreting CH12 cells. Unlike p70 and p120, p102 did not seem to be membrane associated. Taken together, these observations show that IAP expression is regulated developmentally in B lymphocytes. Also, these observations point to possible interactions between IAP genes and other cellular genes.

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“…The size of IAP transcripts found in various murine tumors and tumor cell lines (20,27,31,36,52) varied from 7.0 (35S) to 3.5 kb. Recently, Piko et al (37) reported a predominant and discrete IAP RNA of 5.4 kb in murine embryos.…”

Section: Resultsmentioning

confidence: 99%

Effects of 5-azacytidine on expression of endogenous retrovirus-related sequences in C3H 10T1/2 cells

Hsiao¹,

Gattoni‐Celli²,

Weinstein³

1986

J Virol

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In a previous study (22) we found that transient exposure of C3H 1OT1/2 mouse embryo fibroblasts to 5-azacytidine (5-azaC) induced several changes in growth properties. The treated cells showed progressive changes in morphology, saturation density, growth rate, and serum dependence. By passage 5, the cells had acquired the ability to grow in 0.3% agarose, and by passage 30, they had given rise to fully transformed foci that grew in agarose, agar, and liquid suspension. This progression was rapidly accelerated if the cultures derived from 5-azaC-treated cells were exposed for 48 h to the carcinogen benzo[a]pyrene. The present studies demonstrate that both type C and type A, but not type B, retrovirus-related sequences were expressed in the 5-azaC-treated cells. There was negligible expression of these sequences in the control 10TT/2 cells. The level of expression of the related RNAs tended to correlate with loss of anchorage dependence and other markers of an increase in the transformed phenotype. These changes were associated with hypomethylation of the corresponding cellular DNA sequences, as revealed by differential digestion with the restriction enzymes HpaII and MspI. These studies provide evidence that aberrations in DNA methylation and induction of expression of certain endogenous retroviruses may be one of a series of critical events during the course of multistage carcinogenesis, thus enhancing the evolution of malignant tumor cells.

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Intracisternal A particles: RNA expression and DNA methylation in murine teratocarcinoma cell lines

Cited by 34 publications

References 16 publications

Nucleotide sequences of murine intracisternal A-particle gene LTRs have extensive variability within the R region

Nucleotide sequences of murine intracisternal A-particle gene LTRs have extensive variability within the R region

Expression of intracisternal A-type particles is increased when a B-cell lymphoma differentiates into an immunoglobulin-secreting cell

Effects of 5-azacytidine on expression of endogenous retrovirus-related sequences in C3H 10T1/2 cells

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