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Biomedical subjects

N Ferrer

Publications and source records attributed to N Ferrer.

9 recordsLinked to original sources
PubMed2001

Analysis of the effects of daunorubicin and WP631 on transcription.

The proficiency with which anthracyclines and other DNA-binding drugs target certain sequences in eukaryotic promoters offers a potential approach to interfere with the mechanisms that regulate gene expression in tumor cells. An in vitro transcription assay has been used to compare the ability of the bisintercalating anthracycline WP631 and the monointercalating anthracycline daunorubicin in terms of their ability to inhibit initiation of transcription of the adenovirus major late promoter linked to a G-less transcribed DNA template. Both drugs inhibit basal transcription by RNA polymerase II. However, WP631 is approximately 15 times more efficient at inhibiting transcription initiation from an adenovirus promoter containing an upstream Sp1-protein binding site. The differences in the ability of each drug to inhibit transcription initiation appear to be related to the competition between Sp1 and the anthracyclines for binding to the same site. To see whether WP631's strong effect on transcription can also be observed in cells, we compared the effects of WP631 and other anthracyclines on the transcription of the c-myc gene, which promoter contains Sp1 binding sites. The resulting data suggest that WP631 might circumvent some kinds of tumor resistance at rather low drug concentrations, inhibit c-myc expression in some cell lines, and exert its antitumoral effect by inducing apoptosis.

Animals↗
PubMed1999

The unr gene: evolutionary considerations and nucleic acid-binding properties of its long isoform product.

The unr transcription unit is located just upstream of the N-ras gene in the genome of mammals, in which unr, like N-ras, is ubiquitously expressed. To determine at what point in evolution the unr/N-ras linkage was created, analysis of nucleic acids by Southern and Northern blotting was performed, allowing us to track the presence of the unr gene to the start of vertebrate evolution and the unr/N-ras linkage to the time at which the reptilian and bird lines diverged. We have investigated, with specific anti-unr antibodies, a potential relation between unr protein levels and cellular processes in which N-ras is implicated. A positive correlation in the proliferation of 3T3 cells, but not differentiation of PC12 cells induced by nerve growth factor (NGF), was found. To study the nucleic acid-binding properties of unr, a protein with multiple repeats of a nucleic acid-binding motif, we expressed the long splicing isoform in a eukaryotic cell line and purified it in native form. The results obtained-a high affinity of unr for single-stranded DNA and RNA and lower affinity for double-stranded DNA without regard to nucleic acid sequence, and its intracellular localization in both the nuclear and non-nuclear compartments, together with its ubiquious expression in mammalian tissues-provide molecular information about the function of one of the closest gene tandems in mammalian cells (unr-N-ras).

3T3 Cells↗
PubMed1997

Isolation of high molecular weight DNA for reliable genotyping of transgenic mice.

A fast and reliable method for the PCR characterization of DNA from mouse toes is described. The toes biopsied to tag the mice are incubated for 2 h in proteinase K and heated for 15 min at 95 degrees C. This DNA solution is directly used as a template for PCR amplification. The same procedure can be used for PCR analysis of DNA from other tissues in adult mice, mouse embryos and cultured cells. Because of minimal tissue manipulation, high-quality and high-molecular-weight DNA (fragments larger than 100-200 kb) is isolated. This procedure is performed in a single tube and requires no organic solvent extraction or centrifugation, allowing the isolation of high-molecular-weight DNA suitable for PCR amplification in a fast and reproducible way. Only the tissue excised during mice tagging is used and a large number of animals can be quickly and simultaneously analyzed as required to maintain a transgenic mice colony. In addition, this rapid and efficient procedure represents an alternative to other methods in which, in our experience, inhibition of the PCR amplification occurs when DNA from tail tissues is used.

Animals↗
PubMed1995

Centromeric dodeca-satellite DNA sequences form fold-back structures.

The evolutionarily conserved centromeric dodeca-satellite DNA has an asymmetric distribution of guanine and cytosine residues resulting in one strand being relatively G-rich. This dodeca-satellite G-strand contains a GGGA-tract that is similar to the homopurine tracts found in most telomeric DNA sequences. Here, we show that the dodeca-satellite G-strand forms intramolecular hairpin structures that are stabilized by the formation of non-Watson-Crick G.A pairs as well as regular Watson-Crick G.C pairs. Special stacking interactions are also likely to contribute significantly to the stability of this structure. This hairpin conformation melts at relatively high temperature, around 75 degrees C, and is detected under many different ionic and pH conditions. As judged by electron microscopy visualization, these structures can be formed in a B-DNA environment. Under the same experimental conditions, neither the C-strand nor the double-stranded dodeca-satellite DNA were found to form any unusual DNA structure. A protein activity has been detected that preferentially binds to the single-stranded dodeca-satellite C-strand. The biological relevance of these results is discussed in view of the similarities to telomeric DNA.

Animals↗
PubMed1995

Laparoscopy-assisted vaginal hysterectomy compared with abdominal hysterectomy.

The first 150 consecutive laparoscopic vaginal hysterectomy (LVH) cases done by Creighton University faculty members at Mercy Hospital, Council Bluffs, Iowa and at St Joseph Hospital, Omaha, Nebraska were compared with 194 abdominal hysterectomies (AHs) for benign or noninvasive disease. The results indicate that LVH can be accomplished with low morbidity, low length of stay, and with less patient discomfort than experienced by patients who undergo AH.

Adult↗
PubMed1992

Interaction of trans-acting factors with the proximal promoter of the mouse alpha-fetoprotein gene.

1. The alpha-Fetoprotein (AFP) gene is expressed during fetal life, but not in adult cells. Also, the AFP gene is expressed in most hepatomas. 2. Using gel retardation (band-shift) assays under very stringent conditions we have compared the binding of trans-acting factors to the proximal enhancer (-202, +34) region of the AFP gene. 3. We have detected the presence of two retarded bands in experiments performed with adult rat hepatocytes and the Fa32 cell line (which does not produce AFP) but only one band is observed with the HepG2 cell line (which produces AFP) and fetal liver. 4. We relate the two retarded bands to a glucocorticoid response element and, tentatively, to the C/EBP trans-acting fractor.

Animals↗