生物化学技术

Although it appears to be relatively easy to design ribozymes that cleave their targets and produce detectable cleavage products in vitro, especially when both molecules are quite small, the detection of cleavage products in viva has been remarkably difficult. It is generally assumed th ...

Ribozymes have considerable potential as agents to modify gene expression. Strategies have recently been reported for modifying synthetic hammerhead ribozymes to render them nuclease-resistant while retaining catalytic activity (1). Modified ribozymes therefore offer ...

Successful ribozyme-mediated gene therapy for HIV infection has to take into account several factors: 1. The therapeutic gene must interfere with or shut down the expression of essential viral genes. 2. This re

By June 1995, 112 gene therapy trials had been approved by the NIH Recombinant DNA Advisory Committee (RAC) in the US, involving 500 actual, planned, or projected patients (1–3). Marking trials comprise roughly 20% (25 in total) of all approved studies, while the remainder are considered to have ther ...

Acquired immune deficiency syndrome (AIDS) is a deadly disease that is the pathological consequence of infection with human immunodeficiency virus (HIV). The virus is spread via body fluids, and infection results in progressive immune dysfunction, most notably a loss of CD4+ cells, lead ...

Ribozymes are currently being developed as therapeutic agents against AIDS (1,2). Successful cleavage of the mRNAs produced by HIV or the HIV genome itself could produce improvement by significantly reducing the patients’ viral burden. However, choosing the appropriate target sites ...

Many studies of oligonucleotide binding and catalysis involve small nucleic acid targets with secondary and tertiary structures of little complexity. However, the therapeutic target of antisense oligonucleotides and hammerhead ribozymes, large RNAs, are rich in structures, ...

The chemical synthesis of RNA, like DNA, is carried out in the 3′ to 5′ direction to take advantage of the high chemical reactivity of the 5′-hydroxyl group. Solid-phase chemistry currently provides the most effective means for the scale-up of RNA synthesis. The biological activity of chemically sy ...

The identification of cleavage sites for ribozymes within a particular target RNA exclusively on the basis of sequence informatlon often leads to disappointing failures. Even prediction of secondary structures of the target RNA by computer modeling with a more or less exact prediction ...

As a result of both the therapeutrc (xc1) and structural (2) interest in RNA, there has been an increased demand for larger amounts of oligoribonucleotides. Although great progress has been made in improving the methods for DNA synthesis, such that production of large amounts has become common ...

Transcription by DNA dependent bacteriophage RNA polymerases has become a very powerful technique in molecular biology. Single-stranded RNAs generated by in vitro transcription can be used as substrates in a variety of experiments ranging from splicing and translation to structu ...

Mucins are major differentiated products of mucosal cells throughout the body and are thus important markers of normal and disease development. The use of human colonic cell lines as a model of the adenoma-carcinoma sequence is of particular interest because it allows the changes in express ...

The role of mucus in the protection of intestinal, bronchial, nasopharyngeal, and cervical mucosae has long been recognized, but poorly understood. Research has been stimulated by the expectation that an underlying mucus abnormality might be present, not only in diseases such as cystic fi ...

The generally accepted paradigm for the classification of glycosphingolipids into neutral and acidic classes has proved to be an oversimplification, at least, when considering members of the Invertebrata. The detailed occurrence and frequency of electrically neutral, but amph ...

Glycosphingolipids (GSLs) are primarily located in the plasma membrane of animal cells, but are also found in association with intracellular organelles (1,2) GSLs consist of two structural elements: a lipophilic membrane anchor, the ceramide portion, which is formed by a long chain amin ...

Glycosylphosphatidylinositols (GPIs) are a family of structures that contain the structural motif: Manα1-4GlcNH2α1-6myo-Inositol-1-PO4-lipid. This common substructure suggests that this family of molecules are biosynthetically related and differentiates them f ...

The carbohydrate components in glycoprotein receptors, antibodies, enzymes, toxins, and hormones are increasingly gaining attention as biological recognition signals (1,2). It is, therefore, important to study the conformation of oligosaccharides in solution to better und ...

The majority of proteins are posttranslationally modified, the most significant change being glycosylation, i.e., the attachment of one or more oligosaccharide chains. Because of their long history, but also relative neglect until recently, the terminology for saccharides is dive ...

Over the past decade, numerous nuclear and cytosolic glycoproteins have been shown to be modified by single N-acetylglucosamine (O-GlcNAc) residues attached to the side chain hydroxyl groups of serine or threonine (1–3). This unique postranslational modification (O-GlcNAcylat ...

Sugar moieties on the cell surface play one of the most important roles in cellular recognition. In order to elucidate the molecular mechanism of these cellular phenomena, assessment of the structure of sugar chains is indispensable. However, it is difficult to elucidate the structures of ce ...