Functional diversity in the dynamin family.

The function of the GTPase dynamin has been discussed for several years. It clearly plays a role in vesicle budding, but, despite recent insights, precisely how it functions in this process is still a matter of debate. In addition, it is now clear that dynamin is a member of a large protein family, present in a variety of cellular locations where members apparently perform a range of functions.

Notch signaling: direct or what?

Notch signaling has been implicated in a wide variety of processes from cell-fate decisions, tissue patterning and morphogenesis to human diseases and cancer. A model for Notch directly regulating gene expression has been proposed and at least two signaling pathways have been identified; however, the molecular mechanism(s) by which Notch signaling produces so many outcomes remains unclear.

Transcription: TRF walks the walk but can it talk the talk?

The TBP-related factor TRF binds to a TATA box promoter sequence and mediates basal transcription in vitro. A central question is: does TRF function in vivo to transduce the effects of activators in a tissue-specific fashion?

The Hin dimer interface is critical for Fis-mediated activation of the catalytic steps of site-specific DNA inversion.

Background: Hin is a member of an extended family of site-specific recombinases--the DNA invertase/resolvase family--that catalyze inversion or deletion of DNA. DNA inversion by Hin occurs between two recombination sites and requires the regulatory protein Fis, which associates with a cis-acting recombinational enhancer sequence. Hin recombinase dimers bind to the two recombination sites and assemble onto the Fis-bound enhancer to generate an invertasome structure, at which time they become competent to catalyze DNA cleavage and strand exchange.

Expression patterns of Jagged, Delta1, Notch1, Notch2, and Notch3 genes identify ligand-receptor pairs that may function in neural development.

Notch genes encode receptors for a signaling pathway that regulates neurogenesis. The DSL (Delta/Serrate/lag-2) genes encode ligands that bind and activate Notch. In situ hybridization was used to determine the spatiotemporal expression of Notch1, Notch2, and Notch3, and the DSL ligands, Jagged and Delta 1, in an effort to identify potential ligand-receptor pairs that function during development of the rat nervous system.

Transcriptional activation. A holistic view of the complex.

Recent studies on gene regulation in Saccharomyces cerevisiae support the view that eukaryotic activators stimulate transcription by recruiting an RNA polymerase II holoenzyme to the promoter in a single step.