Cell
Using an expression cloning strategy that relies on a functional assay, we have cloned a novel Xenopus homeobox-containing gene, Siamois. Embryos injected in a ventral-vegetal blastomere with as little as 5 pg of Siamois mRNA develop a complete secondary axis, but the progeny of the injected cells do not participate in the secondary axis formation. In normal development, Siamois mRNA is first detected...
Activation of the receptor tyrosine kinase (RTK) torso defines the spatial domains of expression of the transcription factors tailless and huckebein. Previous analyses have demonstrated that Rasl (p21 ras ) operates upstream of the D-Raf (Raft) serine/threonine kinase in this signaling pathway. By using a recently developed technique of germline mosaics, we find that D-Raf can be activated...
Gelsolin, an 82 kDa actin-binding protein, has potent actin filament-severing activity in vitro. To investigate the in vivo function of gelsolin, transgenic gelsolinnull (Gsn − ) mice were generated and found to have normal embryonic development and longevity. However, platelet shape changes are decreased in Gsn − mice, causing prolonged bleeding times. Neutrophil migration in vivo...
Genetic studies of memory formation in Drosophila have revealed that the formation of a protein synthesis-dependent long-term memory (LTM) requires multiple training sessions. LTM is blocked specifically by induced expression of a repressor isoform of the cAMP-responsive element-binding protein (CREB). Here, we report an enhancement of LTM formation after induced expression of an activator isoform...
In this study, we demonstrate a role for extracentromeric sequences in chromosome inheritance. Genetic analyses indicate that transmission of the Drosophila minichromosome Dp1187 is sensitive to the dosage of nod + , a kinesin-like gene required for the meiotic transmission of achiasmate chromosomes. Minichromosome deletions displayed increased loss rates in females heterozygous for a loss-of-function...
Rho and rac, two members of the ras-related superfamily of small GTPases, regulate the polymerization of actin to produce stress fibers and lamellipodia, respectively. We report here that cdc42, another member of the rho family, triggers the formation of a third type of actin-based structure found at the cell periphery, filopodia. In addition to stress fibers, rho controls the assembly of focal adhesion...
In the plant pathogenic fungus Ustilago maydis, sexual and pathogenic development are controlled by the multiallelic b mating-type locus. The b locus encodes a pair of unrelated homeodomain proteins termed bE and bW, with allelic differences clustering in the N-terminal domains of both polypeptides. Only combinations of bE and bW of different allelic origin are active. We have investigated the underlying...
We show that female sterile mutations of aurora (aur) are allelic to mutations in the lethal complementation group ck 10 . This lies in a cytogenetic interval, 87A7-A9, that contains eight transcription units. A 250 by region upstream of both aur and a divergent transcription unit corresponds to the site of a specific chromatin structure (scs′) previously proposed to be a barrier to insulate...
The Drosophila no distributive disjunction (nod) gene encodes a kinesin-like protein that has been proposed to push chromosomes toward the metaphase plate during female meiosis. We report that the nonmotor domain of the nod protein can mediate direct binding to DNA. Using an antiserum prepared against bacterially expressed nod protein, we show that during prometaphase nod protein is localized on oocyte...
Two interleukin-2 receptor-dependent signaling pathways have thus far been identified: the c-fos/c-jun induction pathway mediated by src family protein-tyrosine kinases and the c-myc induction pathway. Here, we provide evidence for the existence of a third, rapamycin-sensitive pathway, which- results in the induction of another proto-oncogene, bcl-2. In the hematopoietic cell line BAF-1303, the expression...
Lipids and proteins were found to contact a nascent type II membrane protein, as well as a nascent secretory protein, during their insertion into the membrane of the endoplasmic reticulum. This suggests that the protein-conducting channel is open laterally toward the lipid bilayer during an early stage of protein insertion. Contact to lipids was confined to the hydrophobic core region of the respective...
BPAG1 is the major antigenic determinant of autoimmune sera of bullous pemphigoid (BP) patients. It is made by stratified squamous epithelia, where it localizes to the inner surface of specialized integrin-mediated adherens junctions (hemidesmosomes). To explore the function of BPAG1 and its relation to BP, we targeted the removal of the BPAG1 gene in mice. Hemidesmosomes are otherwise normal, but...
Based on the above mechanisms of mRNA degradation, an integrated model of mRNA turnover can be proposed (Figure 1). In this model, all polyadenylated mRNAs would be degraded by the deadenylation-dependent pathway at some rate. In addition to this default pathway, another layer of complexity would come from degradation mechanisms specific to individual mRNAs or to classes of mRNAs. Such mRNA-specific...
Mutations in the PKD1 gene are the most common cause of autosomal dominant polycystic kidney disease (ADPKD). Other PKD1-like loci on chromosome 16 are approximately 97% identical to PKD1. To determine the authentic PKD1 sequence, we obtained the genomic sequence of the PKD1 locus and assembled a PKD1 transcript from the sequence of 46 exons. The 14.5 kb PKD1 transcript encodes a 4304 amino acid protein...