Nanos protein

FIGURE 28-37 Regulatory circuits of the anterior-posterior axis in a Drosophila egg. The bicoid and nanos mRNAs are localized near the anterior and posterior poles, respectively. The caudal, hunchback, and pumilio mRNAs are distributed throughout the egg cytoplasm. The gradients of Bicoid (Bed) and Nanos proteins lead to accumulation of Hunchback protein in the anterior and Caudal protein in the posterior of the egg. Because Pumilio protein requires Nanos protein for its activity as a translational repressor of hunchback, it functions only at the posterior end. 

A different gradient along the A-P axis is formed by the Nanos protein, whose mRNA localizes in the... 

Nanos protein localization in the posterior embryo is intimately coupled to the regulation of translation of nanos mRNA. The nanos mRNA that is not located at the posterior is not translated due to a protein called Smaug that binds the 3 UTR of nanos mRNA. Localization of nanos mRNA at the posterior depends on other proteins as well. One of these is Oskar, whose maternally provided mRNA is transported to the posterior by kinesin, a motor protein that moves along microtubules (Chapter 20). Therefore the kinesin controls, after several intervening steps, the localized activity of a transcription factor (Hunchback). 

Nanos protein inhibits the translation of maternal hb mRNA in the posterior of the fly embryo (see Figure 15-21). Synthesis of Nanos from maternal nanos mRNA is restticted to the posterior by translational connol linked to motor protein-mediated transport of other regulators to the posterior pole. 

Amphoteric hydrophilic Peptides, proteins, poly and oligosaccharides, DNA, RNA Buffer or salt solution (e.g., 0.1 M NaNO,)... 

Given the actual scenario, one can state that the emerging field of nanotechnology represents new effort to exploit new materials as well as new technologies in the development of efficient and low-cost solar cells. In fact, the technological capabilities to manipulate matter under controlled conditions in order to assemble complex supramolecular structures within the range of 100 nm could lead to innovative devices (nano-devices) based on unconventional photovoltaic materials, namely, conducting polymers, fuUerenes, biopolymers (photosensitive proteins), and related composites. 

A major challenge and important application is nano-wiring of electronic circuits mediated by self-assembled DNA or protein structures providing condncting connection between miniaturized electrodes [51,52]. The use of self-assembled DNA for wiring two... 

The conversion of protein-made nanostructnres, e.g., microtnbnles, into conducting nano-wires was also recently investigated [11] Metallization of microtnbnles, by an electrolyte nickel deposition technique, initiated by molecnlar palladinm catalysts, was described. 

Knowledge about protein folding and conformation in biological systems can be used to mimic the design of a desired nanostructure conformation from a particular MBB and to predict the ultimate conformation of the nanostructure [152]. Such biomimetic nano-assembly is generally performed step by step. This wiU allow observation of the effect of each new MBB on the nanostructure. As a result, it is possible to control accurate formation of the desired nanostmcture. Biomimetic controlled and directed assembly can be utilized to investigate molecular interactions, molecular modeling, and study of relationships between the composition of MBBs and the final conformation of the nanostmctures. Immobilization of molecules on a surface could facilitate such studies [153]. 

With these principles in mind, we refer the reader to valuable recent reviews, original reports, and discussions [65-68] of probes consisting of proteins, organic dyes, and nanoparticles such as quantum dots (QDs, [2, 68-77]) and other intriguing particles plastic microspheres and nanoparticles [78], multifunctional encoded particles [79], nanodisk codes [80], nano-flares [81], E-PEBBLES [82], C-dots [83], nanocrystal (NC)-encoded microbeads... 

Dennis, A. M. and Bao, G. (2008). Quantum dot-fluorescent protein pairs as novel fluorescence resonance energy transfer probes. Nano Lett. 8, 1439-45. 

Traditional methods for fabricating nano-scaled arrays are usually based on lithographic techniques. Alternative new approaches rely on the use of self-organizing templates. Due to their intrinsic ability to adopt complex and flexible conformations, proteins have been used to control the size and shape, and also to form ordered two-dimensional arrays of nanopartides. The following examples focus on the use of helical protein templates, such as gelatin and collagen, and protein cages such as ferritin-based molecules. 

Kao, C.C. and Dragnea, B. (2006) Nanopartide-templated assembly of viral protein cages. Nano Letters, 6, 611-615. 

Layered materials are of special interest for bio-immobilization due to the accessibility of large internal and external surface areas, potential to confine biomolecules within regularly organized interlayer spaces, and processing of colloidal dispersions for the fabrication of protein-clay films for electrochemical catalysis [83-90], These studies indicate that layered materials can serve as efficient support matrices to maintain the native structure and function of the immobilized biomolecules. Current trends in the synthesis of functional biopolymer nano composites based on layered materials (specifically layered double hydroxides) have been discussed in excellent reviews by Ruiz-Hitzky [5] and Duan [6] herein we focus specifically on the fabrication of bio-inorganic lamellar nanocomposites based on the exfoliation and ordered restacking of aminopropyl-functionalized magnesium phyllosilicate (AMP) in the presence of various biomolecules [91]. 

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