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Báo cáo sinh học: Gene expression neighborhoods

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Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Gene expression neighborhoods...
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Báo cáo sinh học: "Gene expression neighborhoods" Journal BioMed Central of BiologyMinireviewGene expression neighborhoodsBrian Oliver, Michael Parisi and David ClarkAddress: Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NationalInstitutes of Health, Bethesda, MD 20892, USA.Correspondence: Brian Oliver. E-mail: oliver@helix.nih.govPublished: 1 July 2002Journal of Biology 2002, 1:4The electronic version of this article is the complete one and can befound online at http://jbiol.com/content/1/1/4© 2002 BioMed Central Ltd ISSN 1475–4924 Abstract The finding that neighboring eukaryotic genes are often expressed in similar patterns suggests the involvement of chromatin domains in the control of genes within a genomic neighborhood.Reductionist approaches have been a tremendous boon to In this issue, Spellman and Rubin [3] describe a transcrip-understanding the regulation of transcription, one of the tional profiling study that reveals a surprising correlationvital steps defined by the central dogma of molecular between the organization of genes along Drosophila chro-biology. Gene-by-gene analysis has clearly shown that mosomes and their expression levels. Specifically, neigh-control regions within the DNA sequence bind protein borhoods composed of an average of 15 contiguous genestranscription factors that up- or down-regulate the activity show markedly similar relative expression levels. Althoughof promoters. But now that patterns of gene expression can the average neighborhood contains 15 genes, there is a verybe studied across the entire genome, new findings suggest wide range. These neighborhoods are not obviously com-that, as well as being controlled individually, genes may posed of genes with related functions that might bealso be subject to regulation according to their location expected to exhibit co-regulation, as is the case for thewithin the genome. rRNA, histone, Hox, and globin gene clusters.It has been clear for some time that genomic location has Two other recent papers also suggest that genes with similarsome impact on gene expression. .or example, in various expression levels are non-randomly distributed, in this casespecies when transgenes are removed from their local envi- within the human genome [4,5]. In humans, it has been sug-ronment and reinserted elsewhere in the genome the trans- gested recently that expression neighborhoods serve to regu-genes tend to work more-or-less normally but almost always late housekeeping functions [5]. In Drosophila this is lessshow some alteration in expression due to insertion site - and likely, however, because Spellman and Rubin [3] dem-sometimes the effect on expression is dramatic. That even onstrate that embryos and adults differ dramatically in thesubtle differences in gene expression can have consequences organization of their neighborhoods of similarly expressedin some circumstances is also well known, and is illustrated genes (although one could argue about whether the vermi-by the dramatic effects of minute concentration differences form Drosophila larvae and adults might be expected to showin the gradients of pattern-determining morphogens during two different housekeeping gene sets). The compelling anddevelopment [1], and in the dosage compensation mecha- intriguing Drosophila data are rather mysterious and warrantnisms that have evolved to ensure that X-linked genes are closer examination: what could underlie the observedexpressed at similar levels in male and female animals [2]. similarity of gene expression within neighborhoods? Journal of Biology 2002, 1:44.2 Journal of Biology 2002, Volume 1, Issue 1, Article 4 Oliver et al. http://jbiol.com/content/1/1/4 Perhaps the simplest explanation is that co-regulation that the chromosome is divided into loop domains with within an expression neighborhood may be due to inciden- differing degrees of compaction. Indeed, heterochromatin tal interactions between promoters ...

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