Biomedical subjects

Yue Feng

Publications and source records attributed to Yue Feng.

22 records · Page 2Linked to original sources

PubMed2003

Tyrosine phosphorylation of QKI mediates developmental signals to regulate mRNA metabolism.

The selective RNA-binding protein QKI is essential for myelination in the central nervous system (CNS). QKI belongs to the family of signal transduction activators of RNA (STARs), characteristic of binding RNA and signaling molecules, therefore is postulated to regulate RNA homeostasis in response to developmental signals. Here we report that QKI acts downstream of the Src family protein tyrosine kinases (Src-PTKs) during CNS myelination. QKI selectively interacted with the mRNA encoding the myelin basic protein (MBP). Such interaction stabilized MBP mRNA and was required for the rapid accumulation of MBP mRNA during active myelinogenesis. We found that the interaction between QKI and MBP mRNA was negatively regulated by Src-PTK-dependent phosphorylation of QKI. During early myelin development, tyrosine phosphorylation of QKI in the developing myelin drastically declined, presumably leading to enhanced interactions between QKI and MBP mRNA, which was associated with the rapid accumulation of MBP mRNA and accelerated myelin production. Therefore, developmental regulation of Src-PTK-dependent tyrosine phosphorylation of QKI suggests a novel mechanism for accelerating CNS myelinogenesis via regulating mRNA metabolism.

Amino Acid Sequence↗

PubMed2002

Fragile X mental retardation: misregulation of protein synthesis in the developing brain?

Fragile X mental retardation results from the absence of a selective RNA-binding protein, FMRP. Previous studies demonstrated that FMRP forms messenger ribonucleoprotein (mRNP) complexes to associate with translating polyribosomes, suggesting that FMRP is involved in regulating protein synthesis. We are now facing the changing questions: How does FMRP influence protein synthesis in the brain? What is the target for FMRP in learning and memory? How does the absence of FMRP cause misregulation of protein synthesis, which in turn leads to mental impairment in fragile X syndrome? Models for abnormal neuronal function as a result of misregulated translation due to the absence of FMRP are discussed.

Brain↗

PubMed2002

Melanin-concentrating hormone 1 receptor-deficient mice are lean, hyperactive, and hyperphagic and have altered metabolism.

Melanin-concentrating hormone (MCH) is a cyclic 19-aa hypothalamic neuropeptide derived from a larger prohormone precursor of MCH (Pmch), which also encodes neuropeptide EI (NEI) and neuropeptide GE (NGE). Pmch-deficient (Pmch-/-) mice are lean, hypophagic, and have an increased metabolic rate. Transgenic mice overexpressing Pmch are hyperphagic and develop mild obesity. Consequently, MCH has been implicated in the regulation of energy homeostasis. The MCH 1 receptor (MCH1R) is one of two recently identified G protein-coupled receptors believed to be responsible for the actions of MCH. We evaluated the physiological role of MCH1R by generating MCH1R-deficient (Mch1r-/-) mice. Mch1r-/- mice have normal body weights, yet are lean and have reduced fat mass. Surprisingly, Mch1r-/- mice are hyperphagic when maintained on regular chow, and their leanness is a consequence of hyperactivity and altered metabolism. Consistent with the hyperactivity, Mch1r-/- mice are less susceptible to diet-induced obesity. Importantly, chronic central infusions of MCH induce hyperphagia and mild obesity in wild-type mice, but not in Mch1r-/- mice. We conclude that MCH1R is a physiologically relevant MCH receptor in mice that plays a role in energy homeostasis through multiple actions on locomotor activity, metabolism, appetite, and neuroendocrine function.

Agouti-Related Protein↗

PubMed2002

Neither agouti-related protein nor neuropeptide Y is critically required for the regulation of energy homeostasis in mice.

Agouti-related protein (AgRP), a neuropeptide abundantly expressed in the arcuate nucleus of the hypothalamus, potently stimulates feeding and body weight gain in rodents. AgRP is believed to exert its effects through the blockade of signaling by alpha-melanocyte-stimulating hormone at central nervous system (CNS) melanocortin-3 receptor (Mc3r) and Mc4r. We generated AgRP-deficient (Agrp(-/-)) mice to examine the physiological role of AgRP. Agrp(-/-) mice are viable and exhibit normal locomotor activity, growth rates, body composition, and food intake. Additionally, Agrp(-/-) mice display normal responses to starvation, diet-induced obesity, and the administration of exogenous leptin or neuropeptide Y (NPY). In situ hybridization failed to detect altered CNS expression levels for proopiomelanocortin, Mc3r, Mc4r, or NPY mRNAs in Agrp(-/-) mice. As AgRP and the orexigenic peptide NPY are coexpressed in neurons of the arcuate nucleus, we generated AgRP and NPY double-knockout (Agrp(-/-);Npy(-/-)) mice to determine whether NPY or AgRP plays a compensatory role in Agrp(-/-) or NPY-deficient (Npy(-/-)) mice, respectively. Similarly to mice deficient in either AgRP or NPY, Agrp(-/-);Npy(-/-) mice suffer no obvious feeding or body weight deficits and maintain a normal response to starvation. Our results demonstrate that neither AgRP nor NPY is a critically required orexigenic factor, suggesting that other pathways capable of regulating energy homeostasis can compensate for the loss of both AgRP and NPY.

Agouti-Related Protein↗