News & Views in 2003

In a new study, the presence of a CpG island transgene protects neighboring sequence from DNA methylation during development leading to an open chromatin state that persists in the adult animal. This study suggests the importance of DNA methylation in setting up the epigenome.

Many organisms have sexual recombination, yet its advantages are not fully understood. A new study of the fruit fly Drosophila miranda shows that recombination is essential for removing deleterious mutations from the genome and for allowing beneficial mutations to be incorporated.

A new study shows that a deletion-induced aberrant antisense transcript from a neighboring gene leads to methylation and silencing of the intact gene HBA2 (encoding human α-globin A2) in a family with α-thalassemia. Are there other chromosomal rearrangements that might turn off genes by such antisense-mediated cis-acting methylation?

The spatial organization of the interphase nucleus is related to the differentiation state of the cell and has a role in establishing tissue-specific patterns of gene expression. Investigation of a tissue-specific nuclear protein has identified a new mechanism of cell-specific gene regulation that links nuclear architecture, chromatin structure and gene transcription.

Centrosome abnormalities are linked to genomic instability and are considered one possible cause of cancer. A recent study shows that 'abnormal' inactive centrosomes thought to be deleterious to cells actually provide an accurate backup mechanism to the G2/M checkpoint, allowing specific elimination of nuclei with damaged DNA.

A new study attempts to amplify and clone all the predicted protein-encoding open reading frames (ORFs) for Caenorhabditis elegans. This analysis confirms many of the predicted genes but suggests roughly 50% of them require correction. Recombining the ORFs into a number of different expression systems can generate functional proteomics kits for characterizing protein activity and interaction networks.

Gene products involved in the naturally occurring process of bacterial conjugation are usually encoded on plasmids. A new study shows that in Mycobacterium smegmatis, a unique conjugative transfer is mediated by multiple cis-acting sequences present on the chromosome and requires host recombination functions.

For the detection of human gene mutations to have practical application, clear clinical descriptions of the affected individuals (as well as those clinically affected in whom mutations are not found) should be part of the publication.

Gene transfers from chloroplasts to the nucleus occur naturally over evolutionary time scales but have always been inferred from sequence comparisons, never directly observed. A notable new report has caught plastid-to-nucleus gene transfer in the act, providing exciting opportunities to study its mechanisitic details in the laboratory and its ecological implications in nature.

Eed, a member of the Polycomb group family of chromatin regulators, acts early in mouse development to maintain imprinted X-chromosome inactivation in females. But does this protein also contribute to imprinting on mouse autosomes?

Recent papers have shown the feasibility of classifying humans into categorical populations from their genotypes. How can this be reconciled with the claim that human races are biologically meaningless, and what are the implications for medical genetics projects?

Reliable identification of genetic variants that affect gene regulation is still a challenge in genomics and is expected to have an important role in the molecular characterization of complex traits. A new study describes a robust functional assay that detects the presence of cis-acting polymorphisms that regulate gene transcription.

An altered form of an esterase has been implicated in the development of neurotoxicity after exposure to organophosphates. Mice deficient in this enzyme should be less susceptible to toxicity, but the opposite turns out to be the case.

Genes that are expressed from a single allele in a random manner have one allele replicated earlier than the other. A new study shows that this replication asynchrony is coordinated within chromosome pairs.

Helicobacter pylori induces chronic gastritis in virtually all hosts, yet only a fraction of colonized patients ever develop peptic ulcer disease. A new study shows that binding of the H. pylori virulence determinant VacA by a receptor tyrosine phosphatase, Ptprz, modifies the phosphorylation pattern of gastric epithelial cell proteins and leads to cellular detachment. As activation of Ptprz also results in gastric injury and ulceration in vivo, these findings help explain why VacA-expressing strains of H. pylori augment the risk for peptic ulcer disease

Most nerve axons of higher vertebrates are surrounded by a multilayered myelin membrane that is essential for promotion of rapid nerve conduction. A new study genetically uncouples the myelin-producing function of the myelinating cells from their role in axonal survival, suggesting that neurodegenerative disorders characterized by axonal loss might result from defects in the myelinating cells whether myelin irregularities are apparent or not.