Rice (Oryza sativa), a major staple food, is usually milled to remove the oil-rich aleurone layer that turns rancid upon storage, especially in tropical areas. The remaining edible part of rice grains, the endosperm, lacks several essential nutrients, such as provitamin A. Thus, predominant rice consumption promotes vitamin A deficiency, a serious public health problem in at least 26 countries, including highly populated areas of Asia, Africa, and Latin America. Recombinant DNA technology was used to improve its nutritional value in this respect. A combination of transgenes enabled biosynthesis of provitamin A in the endosperm.

To obtain a functioning provitamin A (beta-carotene) biosynthetic pathway in rice endosperm, we introduced in a single, combined transformation effort the cDNA coding for phytoene synthase (psy) and lycopene beta-cyclase (beta-lcy) both from Narcissus pseudonarcissus and both under the control of the endosperm-specific glutelin promoter together with a bacterial phytoene desaturase (crtI, from Erwinia uredovora under constitutive 35S promoter control). This combination covers the requirements for beta-carotene synthesis and, as hoped, yellow beta-carotene-bearing rice endosperm was obtained in the T(0)-generation. Additional experiments revealed that the presence of beta-lcy was not necessary, because psy and crtI alone were able to drive beta-carotene synthesis as well as the formation of further downstream xanthophylls. Plausible explanations for this finding are that these downstream enzymes are constitutively expressed in rice endosperm or are induced by the transformation, e.g., by enzymatically formed products. Results using N. pseudonarcissus as a model system led to the development of a hypothesis, our present working model, that trans-lycopene or a trans-lycopene derivative acts as an inductor in a kind of feedback mechanism stimulating endogenous carotenogenic genes. Various institutional arrangements for disseminating Golden Rice to research institutes in developing countries also are discussed.

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Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17–30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50°C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90–95%.

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Aberrant expression of TRIM‐containing protein 44 (TRIM44) acts as a promoter in multiple cancers. Here, we investigated the biological functions and clinical significance of TRIM44 in human esophageal cancer (HEC). TRIM44 expression was significantly higher in HEC tissues than corresponding normal tissues at both the mRNA (2.42 ± 0.52 vs 0.99 ± 0.25) and protein (1.01 ± 0.27 vs 0.30 ± 0.13) levels. Patients with high TRIM44 expression showed poor differentiation (P = 1.39 × 10−5), advanced TNM stage (P = 3.87 × 10−4) and, most importantly, significantly poorer prognosis (P = 2.80 × 10−5). TRIM44 played a crucial role in epithelial mesenchymal transition (EMT). A significant correlation was observed between TRIM44 and Ki67 expression. We demonstrated that TRIM44 markedly enhanced HEC cell proliferation, migration, and invasion. Additionally, TRIM44 was involved in the AKT/mTOR signaling pathway and its downstream targets, such as STAT3 phosphorylation. Thus, elevated TRIM44 expression promotes HEC development by EMT via the AKT/mTOR pathway, and TRIM44 may be a novel prognostic indicator for HEC patients after curative resection.

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