von Mering C et al. (2002) Nature "Teamed up for transcription."

Bork P, von Mering C

[Nature, 2002]

The genomes of animals, plants and fungi seem to be relatively disorganized. Genes appear to be randomly distributed, with only a few exceptions: repeats of similar sequences caused by gene duplications, for example, and a limited number of ancient gene clusters containing functionally related genes (such as the Hox genes that are involved in control of animal development). Apart from these, the average gene is generally assumed to be independent of its neighbours, and genomes are constantly rearranged and shuffled. However, in one group of animals the nematodes (small, unsegmented worms) neighboring genes are occasionally assembled into regulatory units called operons. On page 851 of this issue, Blumenthal et al. now report the first whole-genome characterization of such operons in a mulicellular organism, an raise intriguing questions as to how (and why) they have evolved.

Goutte C (2002) Dev Cell "Genetics leads the way to the accomplices of presenilins."

Goutte C

[Dev Cell, 2002]

Presenilins mediate they-secretase cleavage of Notch transmembrane receptors as well as the transmembrane P-amyloid precursor protein (PAPP), but they are not thought to accomplish this alone. Recent genetic screens in C. elegans, presented in this issue of Developmental Cell, identify two genes that are essential to gamma-secretase activity and may interact with presenilins.

Motegi F et al. (2007) J Cell Biol "Revisiting the role of microtubules in C. elegans polarity."

Motegi F, Seydoux G

[J Cell Biol, 2007]

Cells must break symmetry to acquire polarity. Microtubules have been implicated in the induction of asymmetry in several cell types, but their role in the Caenorhabditis elegans zygote, a classic polarity model, has remained uncertain. One study (see Tsai and Ahringer on p. 397 of this issue) brings new light to this problem by demonstrating that severe loss of microtubules impairs polarity onset in C. elegans.