GENE impedance: a natural process for control of gene expression and the origin of RNA interference

New methods in the diagnosis of cancer and gene therapy of cancer based on nanoparticles

Cancer is one of the leading cause of death in the world with the prevalence of >10 million mortalities annually. Current cancer treatments include surgical intervention, radiation, and taking chemotherapeutic drugs, which often kill the healthy cells and result in toxicity in patients. Therefore, researchers are looking for ways to be able to eliminate just cancerous cells. Intra-tumor heterogeneity of cancerous cells is the main obstacle on the way of an effective cancer treatment. However, better comprehension of molecular basis of tumor and the advent of new diagnostic technologies can help to improve the treatment of various cancers. Therefore, study of epigenetic changes, gene expression of cancerous cells and employing methods that enable us to correct or minimize these changes is critically important. In this paper, we will review the recent advanced strategies being used in the field of cancer research.

Coupling of transcription termination to RNAi

In metazoans, the mechanisms of transcriptional termination by RNA polymerase II (Pol II) and accelerated decay of messenger RNA (mRNA) following transcription shutdown are linked by sharing the same sequence elements and mRNA elongation, processing and termination factors. This begs the question, how could one process have two opposite outcomes, making or degrading mRNA? An integrated "allosteric-GENEi-torpedo" model that could explain this paradox predicts participation of two novel factors: (1) An allosteric factor, regulated by a physiological repressor, binds to a unique sequence element of a gene near the site of cleavage and polyadenylation, poly(A) site, and acts on the homologous site on the nascent transcript to cause its cleavage. The conformational changes of this factor determine the fate of nascent RNA, either to get cleaved and processed to mature mRNA for directing protein synthesis, or not to get cleaved and become template for double-stranded (ds) RNA synthesis. (2) A general transcription termination factor, recruited by transcribing Pol II at the poly(A) site, allostrically alters and induces Pol II to switch template from DNA to nascent RNA several hundred nucleotides downstream of the poly(A) site. The template switch disengages Pol II from DNA and effectively terminates transcription. The Pol II with newly acquired RNA-dependent RNA polymerase activity retraces its path, back along the nascent RNA, so generating dsRNA. The extent to which it can retrace this path is determined by the factors influencing the cleavage of the pre-mRNA at the site of polyA addition. If cleavage and polyadenylation occur, the retracing is cut short, the 3' RNA is degraded by an exonuclease and the polymerase is liberated to reinitiate transcription. If the cleavage is inhibited, then a full-length dsRNA can be produced. This can then be subject to cleavage by "Dicer", which generates fragments of approximately 22bp that guide degradation of the cognate mRNA via the RNA interference (RNAi) pathway. This model complements the current "allosteric-torpedo" model of transcription termination, and could explain the apparent paradox of the divergent results of a common biological process.

Human CD14 expressed in seeds of transgenic tobacco displays similar proteolytic resistance and bioactivity with its mammalian-produced counterpart

Human CD14 plays an important role in innate immunity by being the key receptor of lipopolysaccharide found on Gram-negative bacteria. The recently discovered widespread localization of CD14 in secretions and mucosal surfaces reveals its extensive anti-microbial properties and numerous potential medical applications. To produce active recombinant human CD14 (rhCD14) for massive distribution, transgenic tobacco plants were successfully generated to express rhCD14 in the seed endosperm under the control of two versions (1.8 kb and 5.1 kb) of the rice glutelin Gt-1 promoter. Plant-made rhCD14 proteins reached a concentration of 16 microg/g of seeds and showed stability, proteolytic resistance to pepsin digestion and ability to induce the release of pro-inflammatory IL-6 and IL-8 cytokines in presence of LPS. The expression of plant rhCD14 in tobacco seeds constitutes a promising low-cost and abundant supply of this immune protein to further investigate its roles in, impacts on and potential medical applications for the innate immune system.