Francisco Antequera

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Estimation of gene number in mammals is difficult due to the high proportion of noncoding DNA within the nucleus. In this study, we provide a direct measurement of the number of genes in human and mouse. We have taken advantage of the fact that many mammalian genes are associated with CpG islands whose distinctive properties allow their physical separation(More)
Mammalian promoters belong to two different categories in terms of base composition and DNA methylation. In humans and mice, approximately 60% of all promoters colocalize with CpG islands, which are regions devoid of methylation that have a higher G+C content than the genome average, while the rest have a methylation pattern and base composition(More)
The genomes of many higher plant species are the most highly methylated among eukaryotes. We report here that in spite of their heavy methylation, genomic DNAs from four plant species contain a fraction that is very rich in non-methylated sites. The fraction was characterized in maize where it represents about 2.5% of the total nuclear genome. In order to(More)
Genome-wide analysis of replication dynamics requires the previous identification of DNA replication origins (ORIs). However, variability among the ORIs makes it difficult to predict their distribution across the genome on the basis of their sequence. We report here that ORIs in Schizosaccharomyces pombe coincide with discrete chromosomal A+T-rich islands(More)
Heterochromatin comprises tightly compacted repetitive regions of eukaryotic chromosomes. The inheritance of heterochromatin through mitosis requires RNA interference (RNAi), which guides histone modification during the DNA replication phase of the cell cycle. Here we show that the alternating arrangement of origins of replication and non-coding RNA in(More)
CpG islands are normally methylation free in cells of the animal, even when the associated gene is transcriptionally silent. In mouse NIH 3T3 and L cells, however, over half of the islands are heavily methylated. Near identity of the methylated subset in the two cell lines suggested that methylation is confined to genes that are nonessential in culture. In(More)
Eukaryotic DNA replication initiates at multiple points along the chromosomes known as replication origins (ORIs). We have developed a strategy to identify ORIs directly from replication intermediates in the fission yeast Schizosaccharomyces pombe. Mapping of a selection of the novel ORIs onto the genome reveals their preferential localization at intergenic(More)
CpG islands are G+C-rich regions approximately 1 kb long that are free of methylation and contain the promoters of many mammalian genes. Analysis of in vivo replication intermediates at three hamster genes and one human gene showed that the CpG island regions, but not their flanks, were present in very short nascent strands, suggesting that they are(More)
In the "Replicon Theory", Jacob, Brenner and Cuzin proposed the existence of replicators and initiators as the two major actors in DNA replication. Over the years, many protein components of initiators have been shown to be conserved in different organisms during evolution. By contrast, replicator DNA sequences (often referred to as replication origins)(More)