During heart formation, a network of transcription factors and signaling pathways guide cardiac cell fate and differentiation, but the genetic mechanisms orchestrating heart assembly and lumen formation remain unclear. Here, we show that the small GTPase Cdc42 is essential for Drosophila melanogaster heart morphogenesis and lumen formation. Cdc42 genetically interacts with the cardiogenic trans...

We previously reported the transient appearance of an actin superstructure, called the zipper-like structure, during the primary fusion (fusion of mononuclear precursors) and the secondary fusion (fusion of multinucleated cells) of osteoclasts. Here, we focus on the actin-based superstructures that link two precursor cells during the secondary fusion event. In one type of secondary fusion, the ...

Objective: to present our experience with scheduled reoperations in 15 patients with intra-abdominal sepsis. Methods: we have applied a more effective technique consisting of temporary abdominal closure with a nylon mesh sheet containing a zipper. We performed reoperations in the operating room under general anesthesia at an average interval of 84 hours. The revision consisted of debridement of...

The solution structure of an active synthetic peptide containing both the leucine zipper and the adjacent basic domain of the yeast transcription factor GCN4 (residues 220-280) was determined by NMR. The two domains show structurally distinct behaviours. In the absence of DNA, the basic domain is, although very flexible, structured and fluctuating around a helical conformation. The leucine zipp...

Fos and Jun, the protein products of the nuclear proto-oncogenes c-fos and c-jun, associate preferentially to form a heterodimer that binds to DNA and modulates transcription of a wide variety of genes in response to mitogenic stimuli. Both Fos and Jun contain a single leucine zipper region. Previous studies have shown that the leucine zippers of Fos and Jun are necessary and sufficient to medi...

The products of the nuclear oncogenes fos and jun are known to form heterodimers that bind to DNA and modulate transcription. Both proteins contain a leucine zipper that is important for heterodimer formation. Peptides corresponding to these leucine zippers were synthesized. When mixed, these peptides preferentially form heterodimers over homodimers by at least 1000-fold. Both homodimers and th...

Dimerization of the bZIP class of eukaryotic transcriptional control proteins requires a sequence motif called the leucine zipper. We have grown two distinct crystal forms of a 33-amino acid peptide corresponding to the leucine zipper of the yeast transcriptional activator GCN4. This peptide is known to form a dimer of parallel helices in solution. X-ray scattering from both crystal forms shows...

Regulation of gene expression by many transcription factors is controlled by specific combinations of homo- and heterodimers through a short alpha-helical coiled-coil known as a leucine zipper. The dimer interface of a leucine zipper involves side chains of the residues at the a, d, e, and g positions of the (abcdefg)n heptad repeat. To understand the basis for the specificity of dimer formatio...

TGF-beta-stimulated clone-22 (TSC-22) encodes a leucine zipper-containing protein that is highly conserved during evolution. Two homologues are known that share a similar leucine zipper domain and another conserved domain (designated the TSC box). Only limited data are available on the function of TSC-22 and its homologues. TSC-22 is transcriptionally up-regulated by many different stimuli, inc...

These set of notes describe cavity optomechanics in the presence of additional thermo-optic tuning of the cavity resonance. We find that thermo-optic tuning results in correction factors to both the optical spring and optomechanical gain. In addition there is an overall saturation of the optomechanical coupling. These effects can be large for systems with large static thermo-optic tuning and fa...