Identification of DNA Sequence Responsible for 5-Bromodeoxyuridine-Induced Gene Amplification

Biswas, Debajit K.; Hartigan, Jennifer A.; Pichler, Mark H.

doi:10.1126/science.6089335

Cited by 17 publications

(4 citation statements)

References 13 publications

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“…It is known that bromodeoxyuridine induces prolactin synthesis in subclones of a growth hormone (GH)-secreting rat pituitary tumour by a mechanism which involves amplification of the prolactin gene (Biswas & Hanes, 1982). It has been suggested that a 10-3 kilobase DNA segment at the 5' end of the prolactin gene in GH cells is responsible for bromodeoxyuridine-induced gene amplification, and that other genes are also amplified when they are experimentally placed adjacent to this segment by recombinant DNA techniques (Biswas, Hartigan & Pichler, 1985). It will be of interest to learn whether the same DNA segment is present in the somatostatin gene in MTC-M cells and in other neo¬ plastic or normal somatostatin cells.…”

Section: Resultsmentioning

confidence: 98%

Establishment of a continuous somatostatin-producing line of medullary thyroid carcinoma cells from BALB/c mice

Tischler¹,

Lee²,

Costopoulos³

et al. 1986

Journal of Endocrinology

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A continuous line of somatostatin-producing medullary thyroid carcinoma cells was established from a transplantable tumour in BALB/c mice. Virtually all of the somatostatin immunoreactivity co-chromatographed with somatostatin 14. The tumour cells replicated in spinner cultures with a doubling time of approximately 4 days, and the concentration of somatostatin released into the culture medium increased in proportion to the number of cells. Two- to threefold increases in amounts of stored and released somatostatin were observed after treatment of the cells with bromodeoxyuridine. This cell line might be valuable for studies of somatostatin regulation in normal and neoplastic C-cells, and for other studies of C-cell biology which require a mouse model.

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Section: Resultsmentioning

confidence: 98%

Establishment of a continuous somatostatin-producing line of medullary thyroid carcinoma cells from BALB/c mice

Tischler¹,

Lee²,

Costopoulos³

et al. 1986

Journal of Endocrinology

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“…2) suggests that gene insertion has created a structure prone to copy number fluctuation (see Discussion for models for inverted duplication formation and copy number fluctuation). However, an alternative model is that pLPDL may have fortuitously integrated into a genomic region which is unstable when the cells are put under appropriate selective conditions (4,10).…”

Section: Resultsmentioning

confidence: 99%

Formation of an inverted duplication can be an initial step in gene amplification.

Ruiz¹,

Wahl²

1988

Mol. Cell. Biol.

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We have developed a gene transfer approach to facilitate the identification and isolation of chromosomal regions which are prone to high-frequency gene amplification. Such regions are identified by assaying for transformants which show high-frequency resistance to PALA and/or methotrexate by amplification of a vector containing the genes which encode the enzyme targets of these antiproliferative agents. We identified 2 of 47 transformants which displayed high-frequency amplification of the transfected genes, and in this report we describe the analysis of one of them (L46). Molecular analysis of the integration site in transformant L46 revealed that the donated genes were at the center of an inverted duplication which spanned more than 70 kilobase pairs and consisted largely of host DNA. The data suggest that integration of the transfected sequences generates a submicroscopic molecule containing the inverted duplication and at least 750 kilobases of additional sequences. The donated sequences and the host sequences were readily amplified and lost in exponentially growing cultures in the absence of drug selection, which suggests that the extrachromosomal elements are acentric. In contrast to the instability of this region following gene insertion, the preinsertion site was maintained at single copy level under growth conditions which produced copy number heterogeneity in L46. The implications of our results for mechanisms of genetic instability and mammalian gene amplification are discussed.Gene amplification, a localized increase in DNA sequence abundance, is one mechanism by which a cell or organism can increase the level of a gene product required for continued cell function or survival. Examples of amplification have been described in organisms as diverse as bacteria (1), plants (42), insects (10), and humans (53). The numerous examples of gene amplification indicate that many regions of the genomes of these organisms are susceptible to molecular remodeling by this process (for reviews of amplification mechanisms, see references 3, 9, 20, 41, and 44).To examine the molecular mechanisms of mammalian gene amplification, we have developed gene transfer systems which enable us to scan the genome for sites which facilitate amplification (48, 51). The generation of cell lines which amplify transfected drug resistance genes at frequencies higher than 10-3 facilitates the molecular characterization of the initial events of amplification. One example of the usefulness of this approach is provided by our previous studies with a transfected CAD gene which revealed previously unsuspected intermediates in the amplification process. These intermediates, called episomes, have been shown to be submicroscopic autonomously replicating circular precursors of double minute chromosomes (DMs), the typical cytogenetic structures associated with extrachromosomal gene amplification in mammalian cells (7,8,51 In this paper we report the molecular and cellular characterization of one transformant, L46, which exhibited highfrequency ampl...

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“…Early studies of multi-drug resistant cells, showing gene amplification and alterations in the cells growth and differentiation (Biedler et al, 1983), suggest that gene amplification may play a role in these processes. Furthermore, bromodeoxyuridine, which is an inducer of HL60 differentiation, produces gene amplification at specific nucleotide sequences (Bisuras et al, 1984). Yen & co-workers (Yen et al, 1987) have shown that terminal differentiation of HL60 cells depends on a specific event in the S-phase of cell cycle which is associated with DNA replication and may involve gene amplification.…”

Section: Several Protein Kinases Have Been Identified In the Nucleusmentioning

confidence: 99%

The role of protein phosphorylation in the control of cell growth and differentiation

Lord

Bunce²,

Brown³

1988

Br J Cancer

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Identification of DNA Sequence Responsible for 5-Bromodeoxyuridine-Induced Gene Amplification

Cited by 17 publications

References 13 publications

Establishment of a continuous somatostatin-producing line of medullary thyroid carcinoma cells from BALB/c mice

Establishment of a continuous somatostatin-producing line of medullary thyroid carcinoma cells from BALB/c mice

Formation of an inverted duplication can be an initial step in gene amplification.

The role of protein phosphorylation in the control of cell growth and differentiation

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