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J A Hartigan

Publications and source records attributed to J A Hartigan.

7 recordsLinked to original sources
PubMed1987

DNA sequence responsible for the amplification of adjacent genes.

A 10.3-kb DNA fragment in the 5'-flanking region of the rat prolactin (rPRL) gene was isolated from F1BGH(1)2C1, a strain of rat pituitary tumor cells (GH cells) that produces prolactin in response to 5-bromodeoxyuridine (BrdU). Following transfection and integration into genomic DNA of recipient mouse L cells, this DNA induced amplification of the adjacent thymidine kinase gene from Herpes simplex virus type 1 (HSV1TK). We confirmed the ability of this "Amplicon" sequence to induce amplification of other linked or unlinked genes in DNA-mediated gene transfer studies. When transferred into the mouse L cells with the 10.3-5'rPRL gene sequence of BrdU-responsive cells, both the human growth hormone and the HSV1TK genes are amplified in response to 5-bromodeoxyuridine. This observation is substantiated by BrdU-induced amplification of the cotransferred bacterial Neo gene. Cotransfection studies reveal that the BrdU-induced amplification capability is associated with a 4-kb DNA sequence in the 5'-flanking region of the rPRL gene of BrdU-responsive cells. These results demonstrate that genes of heterologous origin, linked or unlinked, and selected or unselected, can be coamplified when located within the amplification boundary of the Amplicon sequence.

Animals↗
PubMed1987

Asynchronous distance between homologous DNA sequences.

The distance between homologous DNA sequences of two species is proposed to be -1/4 ln[det(P)], where P is the conditional probability matrix specifying the proportions of the various nucleotides in the second sequence, corresponding to each of the four nucleotides in the first sequence. A probability model is described which supports this choice of distance. Distance measures based on a constant evolutionary rate assumption are described and compared with the proposed measure. Sampling properties of both types of distance are examined and we conclude by applying the distance measures to mitochondrial DNA sequences of the hominoids.

Base Sequence↗
PubMed1986

Acute ACTH regulation of adrenal corticosteroid biosynthesis. Rapid accumulation of a phosphoprotein.

Two-dimensional gel electrophoresis was used to monitor proteins synthesized in unstimulated control and in adrenocorticotropic hormone (ACTH)- or cAMP-stimulated rat adrenal cells. Four proteins, which have similar proteolytic peptide maps, have been identified. The two found primarily in unstimulated cells are referred to as pb and pa, where pb is the protein with more basic isoelectric point. Similarly, proteins ib and ia were detected only in stimulated cells. The synthesis of pb occurs only in unstimulated cells and that of ib only in stimulated cells. Protein ib accumulates with the same lag time, rate, and stimulant dose response as the increase in steroid hormone synthesis. Pulse-chase studies showed that protein ib is not produced from pb by a post-translational modification. Proteins pb and ib thus seem identical with proteins p and i previously identified in rat adrenal cortex and corpus luteum (Krueger, R.J., and Orme-Johnson, N. R. (1983) J. Biol. Chem. 258, 10159-10167, and Pon, L.A., and Orme-Johnson, N.R. (1986) J. Biol. Chem. 261, 6594-6599). The acidic forms, pa and ia, appear after a longer lag time and are produced at a slower rate than the basic forms. Pulse-chase studies showed that the disappearance of the basic form of each protein occurs concurrently with the appearance of the corresponding acidic form. Addition of [32P]orthophosphate to stimulated adrenal cells allowed direct demonstration that proteins ib and ia are phosphorylated. Moreover, alkaline phosphatase treatment of [35S]methionine-labeled, cAMP-stimulated adrenal cells caused a large decrease in the amounts of ib and ia and the appearance of proteins with the same two-dimensional electrophoretic mobilities as pb and pa. These observations suggest that protein ib may mediate stimulation of steroidogenesis, be produced by an ACTH- or cAMP-dependent, cotranslational phosphorylation of protein pb, and be lost by a cycloheximide-insensitive, post-translational conversion to ia.

Adrenal Cortex Hormones↗
PubMed1984

Mechanism of induction of human chorionic gonadotropin in lung tumor cells in culture. Increased levels of alpha-human chorionic gonadotropin-specific mRNA sequences and benzo(a)pyrene-induced hypomethylation.

Human lung cells (ChaGo) derived from a bronchogenic carcinoma produce human chorionic gonadotropin (hCG), predominantly the alpha subunit of the glycoprotein hormone, under culture conditions. Treatment of the cells with the polycyclic aromatic hydrocarbons, benzo(a)pyrene (BaP) or dimethylbenzanthracene, at concentrations which do not affect cell growth or macromolecular synthesis, stimulates the production of hCG in these cells. The levels of alpha hCG-specific mRNA (mRNA alpha hCG) sequences in total poly(A)+ RNA isolated from control and drug-treated ChaGo cells are determined by the dot hybridization technique using 32P-labeled, cloned cDNA alpha hCG probe. A concentration-dependent increase in the levels of mRNA alpha hCG sequences in BaP or dimethylbenzanthracene-treated ChaGo cells has been observed. The increase in the level of mRNA alpha hCG sequences can be detected after treatment of the cells with either of the drugs for 24 h, and this level attains its maximum within 48-72 h following drug treatment. A comparative study of the restriction endonuclease (MspI/HpaII) digestion patterns of the control and BaP-treated cell DNA suggests that the internal "C" residues of the -CCGG- sequences in the alpha hCG gene of untreated cells are highly methylated; whereas the internal C residues of the same MspI/HpaII recognition sequences in the alpha hCG gene are comparatively less methylated in BaP-treated cell DNA.

Benzo(a)pyrene↗
PubMed1984

Identification of DNA sequence responsible for 5-bromodeoxyuridine-induced gene amplification.

Bromodeoxyuridine (BrdUrd) treatment of the prolactin nonproducing subclone of GH cells (rat pituitary tumor cells) induces amplification of a 20-kilobase DNA fragment including all of the prolactin gene coding sequences. This amplified DNA segment, which is flanked by two unamplified regions, thus designates a unit of BrdUrd-induced amplified sequence. Cloned DNA segments, 10.3 kilobases long, from the 5' end of the rat prolactin gene of BrdUrd-responsive and -nonresponsive cells, were ligated to the thymidine kinase gene of herpes simplex virus type 1 (HSV1TK), and the hybrid DNA was transferred to thymidine kinase-deficient mouse fibroblast cells by transfection. The HSV1TK gene and the rat prolactin gene were amplified together in drug-treated transfectants carrying the hybrid DNA HSV1TK gene and rat prolactin gene of BrdUrd-responsive GH cells. These results suggest that the 10.3-kilobase DNA segment at the 5' end of the rat prolactin gene of BrdUrd-responsive GH cells carries the information for drug-induced gene amplification (amplicon) and that another gene, such as the HSV1TK gene, is also amplified when the latter is placed adjacent to this segment.

Animals↗
PubMed1973

Clustering.

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