DNA 2000: International Symposium on the State-of-the-Art in Genetic Analysis, June 1-3, 2000, Boston, U.S.A.

DNA 2000, an international symposium on state-of-the-art genetic analysis, was held at the Back Bay Hilton in Boston, Massachusetts, on 1-3 June, 2000. Meeting highlights are described. The meeting was organized and sponsored by the California Separation Science Society (CaSSS; www.casss.org) and other co-sponsors including the Human Genome Organisation (HUGO). DNA 2000 brought together a group of specialists in DNA detection and analysis methods from around the world in a venue presenting not only new technologies but also their applications in candidate gene studies, molecular diagnosis, analysis of complex diseases, and even studying the origin and evolution of humans.

Going digital: image preparation for biomedical publishing.

Authors are more often being held responsible for readying their own data figures for digital publication by scanning them at the proper resolution and preparing them for presentation in both print and on-line journals. In this manner, the visuals can be printed at the highest quality the publisher can provide and be ready for rapid electronic distribution on the Internet. Therefore, authors must become knowledgeable in the visual preparation process in order to generate electronic images that will be as true a representation of the original image as possible. Perfecting this procedure can be a learning experience and often requires some experimentation. When accomplished, the author will have more control of exactly how the images will look before they are published. In addition to the scan resolution, the type of digital scanner and software applications used are very important, and instruction manuals should be followed closely so as to understand the full potential of the digitizing equipment. Anat Rec (New Anat): 257:128-136, 1999.

Stimulation of the mouse rRNA gene promoter by a distal spacer promoter.

We show that the mouse ribosomal DNA (rDNA) spacer promoter acts in vivo to stimulate transcription from a downstream rRNA gene promoter. This augmentation of mammalian RNA polymerase I transcription is observed in transient-transfection experiments with three different rodent cell lines, under noncompetitive as well as competitive transcription conditions, over a wide range of template concentrations, whether or not the enhancer repeats alone stimulate or repress expression from the downstream gene promoter. Stimulation of gene promoter transcription by the spacer promoter requires the rDNA enhancer sequences to be present between the spacer promoter and gene promoter and to be oriented as in native rDNA. Stimulation also requires that the spacer promoter be oriented toward the enhancer and gene promoter. However, stimulation does not correlate with transcription from the spacer promoter because the level of stimulation is not altered by either insertion of a functional mouse RNA polymerase I transcriptional terminator between the spacer promoter and enhancer or replacement with a much more active heterologous polymerase I promoter. Further analysis with a series of mutated spacer promoters indicates that the stimulatory activity does not reside in the major promoter domains but requires the central region of the promoter that has been correlated with enhancer responsiveness in vivo.

Expression of mouse and frog rRNA genes: transcription and processing.

This article summarizes a number of lines of investigation of rRNA gene expression that are ongoing in the laboratory. These studies focus on mouse and frog, two distant vertebrate species. One major conclusion is that the basic properties of rRNA gene expression appear remarkably well conserved in evolution, with only relatively minor perturbations between frog and mouse, contrary to the common interpretation of the species-selectively between mouse and human rDNA transcription (e.g., 1). This is true both for the process of rDNA transcription and for the subsequent rRNA processing event.

Enhancers for RNA polymerase I in mouse ribosomal DNA.

The intergenic spacer of the mouse ribosomal genes contains repetitive 140-base-pair (bp) elements which we show are enhancers for RNA polymerase I transcription analogous to the 60/81-bp repetitive enhancers (enhancers containing a 60-bp and an 81-bp element) previously characterized from Xenopus laevis. In rodent cell transfection assays, the 140-bp repeats stimulated an adjacent mouse polymerase I promoter when located in cis and competed with it when located in trans. Remarkably, in frog oocyte injection assays, the 140-bp repeats enhanced a frog ribosomal gene promoter as strongly as did the homologous 60/81-bp repeats. Mouse 140-bp repeats also competed against frog promoters in trans. The 140-bp repeats bound UBF, a DNA-binding protein we have purified from mouse extracts that is the mouse homolog of polymerase I transcription factors previously isolated from frogs and humans. The DNA-binding properties of UBF are conserved from the mouse to the frog. The same regulatory elements (terminators, gene and spacer promoters, and enhancers) have now been identified in both a mammalian and an amphibian spacer, and they are found in the same relative order. Therefore, this arrangement of elements probably is widespread in nature and has important functional consequences.