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Anterior Silk Gland (anterior + silk_gland)

Distribution by Scientific Domains
Chemistry75%

Selected Abstracts

Presence of membrane ecdysone receptor in the anterior silk gland of the silkworm Bombyx mori

FEBS JOURNAL, Issue 15 2004
Mohamed Elmogy
Nongenomic action of an insect steroid hormone, 20-hydroxyecdysone (20E), has been implicated in several 20E-dependent events including the programmed cell death of Bombyx anterior silk glands (ASGs), but no information is available for the mode of the action. We provide evidence for a putative membrane receptor located in the plasma membrane of the ASGs. Membrane fractions prepared from the ASGs exhibit high binding activity to [3H]ponasterone A (PonA). The membrane fractions did not contain conventional ecdysone receptor as revealed by Western blot analysis using antibody raised against Bombyx ecdysone receptor A (EcR-A). The binding activity was not solubilized with 1,m NaCl or 0.05% (w/v) MEGA-8, indicating that the binding sites were localized in the membrane. Differential solubilization and temperature-induced phase separation in Triton X-114 showed that the binding sites might be integrated membrane proteins. These results indicated that the binding sites are located in plasma membrane proteins, which we putatively referred to as membrane ecdysone receptor (mEcR). The mEcR exhibited saturable binding for [3H]PonA (Kd = 17.3 nm, Bmax = 0.82 pmol·mg,1 protein). Association and dissociation kinetics revealed that [3H]PonA associated with and dissociated from mEcR within minutes. The combined results support the existence of a plasmalemmal ecdysteroid receptor, which may act in concert with the conventional EcR in various 20E-dependent developmental events. [source]

Function of a TGF-, inducible nuclear protein in the silk gland in Bombyx mori

INSECT MOLECULAR BIOLOGY, Issue 2 2009
J-L. Wang
Abstract A TGF-, inducible nuclear protein 1 (BmTINP1) was cloned from silkworm, Bombyx mori. Polyclonal antibodies against BmTINP1 were produced and subsequently used in immunoblotting and immunohistochemistry analyses. The immunoblotting analyses demonstrated that BmTINP1 was specifically expressed in the anterior silk gland (ASG) and the middle silk gland (MSG) but not in the posterior silk gland (PSG). There were two bands that suggested the existence of an isoform of BmTINP1. The expression profiles of BmTINP1 in ASGs and MSGs were similar, and they manifested a high level of expression throughout the period during which silk gland grew exponentially. Immunohistochemistry results revealed that BmTINP1 was translocated from the nucleus into the cytoplasm when larvae developed from the 4th-HCS into the 5th instar. 20-hydroxyecdysone (20E) promotes the translocation, while the methoprene [a juvenile hormone (JH) analog] restrains the process. Our findings indicate that BmTINP1 is involved in silk produce along with the rapid growth of ASGs and MSGs during the last instar larvae, and the process could be regulated by hormones via control of BmTINP1 translocation from the nucleus to the cytoplasm. [source]

Presence of membrane ecdysone receptor in the anterior silk gland of the silkworm Bombyx mori

FEBS JOURNAL, Issue 15 2004
Mohamed Elmogy
Nongenomic action of an insect steroid hormone, 20-hydroxyecdysone (20E), has been implicated in several 20E-dependent events including the programmed cell death of Bombyx anterior silk glands (ASGs), but no information is available for the mode of the action. We provide evidence for a putative membrane receptor located in the plasma membrane of the ASGs. Membrane fractions prepared from the ASGs exhibit high binding activity to [3H]ponasterone A (PonA). The membrane fractions did not contain conventional ecdysone receptor as revealed by Western blot analysis using antibody raised against Bombyx ecdysone receptor A (EcR-A). The binding activity was not solubilized with 1,m NaCl or 0.05% (w/v) MEGA-8, indicating that the binding sites were localized in the membrane. Differential solubilization and temperature-induced phase separation in Triton X-114 showed that the binding sites might be integrated membrane proteins. These results indicated that the binding sites are located in plasma membrane proteins, which we putatively referred to as membrane ecdysone receptor (mEcR). The mEcR exhibited saturable binding for [3H]PonA (Kd = 17.3 nm, Bmax = 0.82 pmol·mg,1 protein). Association and dissociation kinetics revealed that [3H]PonA associated with and dissociated from mEcR within minutes. The combined results support the existence of a plasmalemmal ecdysteroid receptor, which may act in concert with the conventional EcR in various 20E-dependent developmental events. [source]

The expression patterns of a eukaryotic initiation factor 3 subunit H in the silk glands in Bombyx mori

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Jia-Lin Wang
Abstract Eukaryotic initiation factor 3 subunit H has been characterized in many organisms, and it has been found to play many roles including help regulate translation initiation. In this work, we studied the tissue distribution and expression profiles of Bombyx mori (B. mori) eIF3 subunit H (BmeIF3h). BmeIF3h was prominently expressed in silk glands, with anterior silk glands (ASGs), middle silk glands (MSGs), and posterior silk glands (PSGs) all expressing BmeIF3h. The expression levels of BmeIF3h in MSGs and PSGs were higher than that in ASGs during 0 d and 2 d of the 5th instar larvae. The expression levels of BmeIF3h in MSGs and PSGs were up-regulated once the silk glands began to synthesize silk protein during the feeding stage of the 4th instar larvae. Immunohistochemistry showed that BmeIF3h was distributed in the cytoplasm of MSGs cells and in both the nucleus and the cytoplasm of PSGs cells. These data suggest that BmeIF3h had different action behaviors in the MSGs and PSGs related to the production of the silk glue proteins and silk fibre proteins, respectively. © 2010 Wiley Periodicals, Inc. [source]