Izumi N et al. (2014) Genes Dev "Diversity of the piRNA pathway for nonself silencing: worm-specific piRNA biogenesis factors."

Izumi N, Tomari Y

[Genes Dev, 2014]

The PIWI-interacting RNA (piRNA) pathway protects animal germline cells from transposable elements and other genomic invaders. Although the genome defense function of piRNAs has been well established, the mechanisms of their biogenesis remain poorly understood. In this issue of Genes & Development, three groups identify novel factors required for piRNA biogenesis in Caenorhabditis elegans. These works greatly expand our understanding of the piRNA pathway in worms, highlighting both its shared and its unique properties.

Mizushima N (2014) Nat Cell Biol "Sugar modification inhibits autophagosome-lysosome fusion."

Mizushima N

[Nat Cell Biol, 2014]

Autophagy is an intracellular degradation system that is mediated by orchestrated functions of membranes and proteins. A genetic screen in Caenorhabditis elegans revealed that O-linked N-acetylglucosamine modification of the SNARE protein SNAP-29 negatively regulates SNARE-dependent fusion between autophagosomes and lysosomes. This regulatory mechanism is conserved in mammals.

Vincenz L et al. (2014) Cell "Sugarcoating ER Stress."

Vincenz L, Hartl FU

[Cell, 2014]

The hexosamine biosynthetic pathway (HBP) generates metabolites for protein N- and O-glycosylation. Wang et al. and Denzel et al. report a hitherto unknown link between the HBP and stress in the endoplasmic reticulum. These studies establish the HBP as a critical component of the cellular machinery of protein homeostasis.

Podbilewicz B (2004) Nat Cell Biol "Sweet control of cell migration, cytokinesis and organogenesis."

Podbilewicz B

[Nat Cell Biol, 2004]

Why are proteins glycosylated? On the basis of new studies, I propose two models to clarify the specific functions of glycosylation in worms. The first explains how intra- and inter-cellular trafficking of an N-glycosylated disintegrin-metalloprotease guides somatic gonadal cells through their migratory route, determining the shape of an organ. The second explains how rigid coats of secreted chondroitin proteoglycans bend membranes to drive cytokinesis and epithelial invagination.

Hodgkin J (2002) Genes Dev "The remarkable ubiquity of DM domain factors as regulators of sexual phenotype: ancestry or aptitude?"

Hodgkin J

[Genes Dev, 2002]

The CM domain is a cysteine-rich DNA-binding motif first recognized in proteins encoded by the Drosophila set determination gene doublesex (Erdman and Burtis 1993; Zhu et al. 2000). As the name doublesex (dsx) suggests, this gene has functions in both sexes: Its transcripts undergo sex-specific alternative splicing, so that it can encode either a male-specific isoform, DSX(M), or a female-specific isoform, DSX(F) (Baker and Wolfner 1988; Burtis and Baker 1989). These proteins have the same N-terminal DNA-binding domain, but different C termini that confer different regulatory properties on the two forms. The expression of DSX(M) directs male development, and the expression of DSX(F) directs female development, throughout most of the somatic tissues of the fruit fly.