Thein vivo ligand-binding function and ligand-binding activity of the Dro-sophila melanogaster retinoid-X receptor (RXR) ortholog, ultraspiracle,
toward natural farnesoid products of the ring gland were assessed. Using
an equilibrium fluorescence-binding assay, farnesoid products in the juven-ile hormone (JH) biosynthesis pathway, and their epoxy derivatives, were
measured for their affinity constant for ultraspiracle (USP).
A pair of nuclear receptors, ecdysone receptor (EcR) and ultraspiracle
(USP), heterodimerize and transduce ecdysteroid signals. The EcR and its
nonsteroidal ligands are being developed for regulation of transgene expres-sion in humans, animals and plants. In mammalian cells, EcR:USP
heterodimers can function in the absence of ligand, but EcR⁄retinoid X
receptor (EcR:RXR) heterodimers require the presence of ligand for activa-tion.
Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành y đề tài: Retinoid X receptor and peroxisome proliferator-activated receptor-gamma agonists cooperate to inhibit matrix metalloproteinase gene expression...
cDNAs of the ecdysone receptor and the retinoid X receptor were cloned
from the Japanese scorpion Liocheles australasiae, and the amino acid
sequences were deduced. The full-length cDNA sequences of theL. austra-lasiae ecdysone receptor and the L. australasiaeretinoid X receptor were
2881 and 1977 bp in length, respectively, and the open reading frames
encoded proteins of 560 and 414 amino acids. The amino acid sequence of
Retinoic acid receptor (RAR) and retinoid X receptor are ligand-induced
transcription factors that belong to the nuclear receptor family. The
receptors are activated by small hydrophobic compounds, such as
all-trans-retinoic acid and 9-cis-retinoic acid, respectively. Interestingly,
these receptors are also targets for a number of exogenous compounds.
Gene switches have potential applications for the regulation of transgene
expression in plants and animals. Recently, we have developed a two-hybrid ecdysone receptor (EcR) gene switch using chimera 9 [CH9, a chi-mera between helices 1–8 ofHomo sapiensretinoid X receptor (HsRXR)
and helices 9–12 ofLocusta migratoriaRXR (LmRXR)] as a partner for
Choristoneura fumiferanaEcR (CfEcR).
Skeletal muscle contractions power human body movements and are essential for
maintaining stability. Skeletal muscle tissue accounts for almost half of the human body
mass and, in addition to its power-generating role, is a crucial factor in maintaining
homeostasis. Given its central role in human mobility and metabolic function, any
deterioration in the contractile, material, and metabolic properties of skeletal muscle has an
extremely important effect on human health.
Insect development is driven by the action of ecdysteroids on morphogenetic
processes. The classic ecdysteroid receptor is a protein heterodimer com-posed of two nuclear receptors, the ecdysone receptor (EcR) and Ultraspira-cle (USP), the insect ortholog of retinoid X receptor. The functional
properties of EcR and USP vary among insect species, and provide a basis
for identifying novel and species-specific insecticidal candidates that disrupt
this receptor’s normal activity.
Fatty acids can stimulate the secretory activity of insulin-producing beta-cells. At elevated concentrations, they can also be toxic to isolated beta-cells. This toxicity varies inversely with the cellular ability to accumulate
neutral lipids in the cytoplasm. To further examine whether cytoprotection
can be achieved by decreasing cytoplasmic levels of free acyl moieties, we
investigated whether palmitate toxicity is also lowered by stimulating its
Retinoid receptors are ligand-dependent transcription
factors belonging to the nuclear receptor superfamily.
Retinoic acid (RARa, b, c) and retinoid X (RXRa, b, c)
receptors mediate the retinoid/rexinoid signal to the
transcriptional machineries by interacting at the first level
with coactivators or corepressors, which leads to the
recruitment of enzymatically active noncovalent com-plexes at target gene promoters.
Analyses of integration of two-hormone signaling through the vertebrate
nuclear hormone receptors, for which the retinoid X receptor is one part-ner, have generated a number of mechanistic models, including those des-cribed as ‘subordination’ models wherein ligand-activation of one partner
is subordinate to the liganded state of the other partner.
To develop an ecdysone receptor (EcR)-based inducible
gene regulation system, several constructs were prepared by
fusing DEF domains of Choristoneura fumiferanaEcR
(CfEcR),C. fumiferanaultraspiracle (CfUSP),Mus muscu-lus retinoid X receptor (MmRXR) to either GAL4 DNA
binding domain (DBD) or VP16 activation domain. These
constructs were tested in mammalian cells to evaluate their
ability to transactivate luciferase gene placed under the
control of GAL4 response elements and synthetic TATAA