An insulin-like growth factor-like peptide promotes ovarian development in the silkmoth Bombyx mori.

Insulin family peptides are known to be key regulators of growth and metabolism in insects and vertebrates. Insects have two types of insulin family peptides: insulin-like peptides and insulin-like growth factor (IGF)-like peptides (IGFLPs). We recently demonstrated that an IGFLP in the silkmoth, Bombyx mori (BIGFLP) promotes the growth of the genital imaginal disc ex vivo.

Identification and Analysis of a Gene with Potential to Repress the IMD Pathway in .

The IMD pathway is one of the signal transduction pathways that regulates innate immune responses in . To understand the regulation mechanism of the IMD pathway, we performed a mis-expression screening and identified a gene, , which potentially repress the expression of the downstream target genes of the IMD pathway. We confirmed that was expressed in the fat body where the IMD pathway is functional and that the overexpression of increases susceptibility.

Microtubule-dependent balanced cell contraction and luminal-matrix modification accelerate epithelial tube fusion.

Connection of tubules into larger networks is the key process for the development of circulatory systems. In Drosophila development, tip cells of the tracheal system lead the migration of each branch and connect tubules by adhering to each other and simultaneously changing into a torus-shape. We show that as adhesion sites form between fusion cells, myosin and microtubules form polarized bundles that connect the new adhesion site to the cells' microtubule-organizing centres, and that E-cadherin and retrograde recycling endosomes are preferentially deposited at the new adhesion site.

Cellular Defense and Sensory Cell Survival Require Distinct Functions of ebi in Drosophila.

The innate immune response and stress-induced apoptosis are well-established signaling pathways related to cellular defense. NF-κB and AP-1 are redox-sensitive transcription factors that play important roles in those pathways. Here we show that Ebi, a Drosophila homolog of the mammalian co-repressor molecule transducin β-like 1 (TBL1), variously regulates the expression of specific genes that are targets of redox-sensitive transcription factors.

Antiviral autophagy restrictsRift Valley fever virus infection and is conserved from flies to mammals.

Autophagy has been implicated as a component of host defense, but the significance of antimicrobial autophagy in vivo and the mechanism by which it is regulated during infection are poorly defined. Here we found that antiviral autophagy was conserved in flies and mammals during infection with Rift Valley fever virus (RVFV), a mosquito-borne virus that causes disease in humans and livestock. In Drosophila, Toll-7 limited RVFV replication and mortality through activation of autophagy.

fat facets induces polyubiquitination of Imd and inhibits the innate immune response in Drosophila.

The IMD pathway is one of the major regulators of the innate immune response in Drosophila. Although extensive analysis of the IMD pathway has been carried out, precise mechanisms for how each target gene of the pathway is down-regulated remain to be clarified. Here, we carried out genetic screening and found that fat facets (faf), which encodes a deubiquitinating enzyme, inhibited the expression of the target genes of the IMD pathway.

Functional analysis of Toll-related genes in Drosophila.

The Drosophila genome encodes a total of nine Toll and related proteins. The immune and developmental functions of Toll and 18Wheeler (18W) have been analyzed extensively, while the in vivo functions of the other Toll-related proteins require further investigation. We performed transgenic experiments and found that overexpression of Toll-related genes caused different extents of lethality and developmental defects.

A fat body-derived IGF-like peptide regulates postfeeding growth in Drosophila.

Members of the insulin family of peptides have conserved roles in the regulation of growth and metabolism in a wide variety of metazoans. Here we show that Drosophila insulin-like peptide 6 (DILP6), which is structurally similar to vertebrate insulin-like growth factor (IGF), is predominantly expressed in the fat body, a functional equivalent of the vertebrate liver and adipocytes. This expression occurs during the postfeeding stage under the direct regulation of ecdysteroid.

Helicase89B is a Mot1p/BTAF1 homologue that mediates an antimicrobial response in Drosophila.

We have identified a novel component, Helicase89B, that is required for the inducible antimicrobial response in Drosophila larvae by means of a P-element insertional genetic screen. Helicase89B belongs to the Mot1p/BTAF1 subfamily of SNF2-like ATPases. This subfamily can interact with TATA-binding proteins, but whether the interaction leads to gene activation or repression is being debated.

A Drosophila p38 orthologue is required for environmental stress responses.

The p38 mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signalling mechanism involved in processes as diverse as apoptosis, cell fate determination, immune function and stress response. Aberrant p38 signalling has been implicated in many human diseases, including heart disease, cancer, arthritis and neurodegenerative diseases. To further understand the role of p38 in these processes, we generated a Drosophila strain that is null for the D-p38a gene.

Toll and Toll-9 in Drosophila innate immune response.

In both insects and mammals, members of the Toll receptor family play important roles in the initial events leading to the activation of immunity genes. The prototypic Toll in Drosophila appears to be activated by a host protein ligand after microbial stimulation. The cellular events and the biological response after Toll activation, however, require further investigation.

Multimerization and interaction of Toll and Spätzle in Drosophila.

The Toll family of receptors is required for innate immune response to pathogen-associated molecules, but the mechanism of signaling is not entirely clear. In Drosophila the prototypic Toll regulates both embryonic development and adult immune response. We demonstrate here that the host protein Spätzle can function as a ligand for Toll because Spätzle forms a complex with Toll in transgenic fly extracts and stimulates the expression of a Toll-dependent immunity gene, drosomycin, in adult flies.

Expression and characterization of the Drosophila X11-like/Mint protein during neural development.

The X11-like (X11L) protein was originally isolated as a protein bound to the cytoplasmic domain of the beta-amyloid precursor protein (APP), which is associated with Alzheimer's disease. In mammals, X11L is believed to play an important role in the regulation of APP metabolism. Here we isolated and characterized the Drosophila X11L (dX11L) protein, also may be referred to this protein as Drosophila Mint (dMint), Lin 10 (dLin10) or X11 (dX11), is thought to be expressed in neuronal tissues from late embryonic through to the adult stages of the fly.

Interaction of Alzheimer's beta -amyloid precursor family proteins with scaffold proteins of the JNK signaling cascade.

We have isolated a novel protein based on its association with Drosophila APP-like protein (APPL), a homolog of the beta-amyloid precursor protein (APP) that is implicated in Alzheimer's disease. This novel APPL-interacting protein 1 (APLIP1) contains a Src homology 3 domain and a phosphotyrosine interaction domain and is expressed abundantly in neural tissues. The phosphotyrosine interaction domain of APLIP1 interacts with a sequence containing GYENPTY in the cytoplasmic domain of APPL.

The Drosophila Toll-9 activates a constitutive antimicrobial defense.

The Toll family of transmembrane proteins participates in signaling infection during the innate immune response. We analyzed the nine Drosophila Toll proteins and found that wild-type Toll-9 behaves similar to gain-of-function Toll-1. Toll-9 activates strongly the expression of drosomycin, and utilizes similar signaling components to Toll-1 in activating the antifungal gene.

The brain neurosecretory cells of the moth Samia cynthia ricini: Immunohistochemical localization and developmental changes of the Samia homologues of the Bombyx prothoracicotropic hormone and bombyxin.

We produced mouse antisera against synthetic peptides corresponding to the sequences of the Samia cynthia ricini homologues of the Bombyx mori PTTH and bombyxin. Immunohistochemical analyses of the Samia cephalic neuroendocrine system using these antisera were performed to identify the neurosecretory cells (NSC) containing the PTTH and bombyxin homologues and to examine the developmental changes in their amounts in the NSC. The results show that the PTTH and bombyxin homologues are produced by two pairs of dorsolateral and 16 pairs of dorsomedial NSC of Samia brain, respectively, and both are transported to, and released from, the corpora allata.