细胞功能测定

Local micro-environmental cues consisting of soluble cytokines, extra-cellular matrix (ECM), and cell–cell contacts are determining factors in stem cell fate. These extrinsic cues form a ‘niche’ that governs a stem cell’s decision to either self-renew or differentiate into one or more c ...

The ability of cell-penetrating peptides (CPPs) to cross cell membranes and transport cargo into cells makes them an attractive tool for the molecular engineering of stem cells. Even though the exact mechanism of transduction remains unclear, their potential has been demonstrated for d ...

Tissue-resident stem cells or primitive progenitors play an integral role in homeostasis of most organ systems. Recent developments in methodologies to isolate and culture embryonic and somatic stem cells have many new applications poised for clinical and preclinical trials, whi ...

The identification and cloning of thrombopoietin was certainly a defining moment for the study of megakaryopoiesis and thrombopoiesis ex vivo. This and other progresses made in the development of culture processes for hematopoietic stem cells have paved the way for ongoing clinical t ...

Interactions between haemopoietic stem cells (HSC) and their microenvironment serve multiple functions including the attraction to and retention and regulation in the bone marrow HSC niche. However, the cell adhesion molecules involved, their HSC receptors and the mechanisms un ...

A growing number of specific cell types have been successfully derived from embryonic stem cells (ES cells), including a variety of neural cells. In vitro generated cells need to be extensively characterized to establish functional equivalency with their in vivo counterparts. The ultim ...

We describe a technological approach permitting the massive expansion of CD34+ stem cells and their 100% conversion ex vivo into mature red blood cells (RBC). The protocol comprises three steps: a first step consisting of cell proliferation and induction of erythroid differentiation in a l ...

The isolation and experimental manipulation of multipotent precursors is of increasing therapeutic relevance. We recently reported the generation of cultures of Skin-derived Precursors (‘SKPs’), multipotent cells that can be isolated from the dermis of embryonic, neonatal, and ...

Neural transplantation has been a long-standing goal for the treatment of neurological injury and disease. The recent discovery of persistent pools of neural stem cells within the adult mammalian brain has reignited interest in transplant therapeutics. Since neural stem cells are se ...

Islet grafts have demonstrated that patients with diabetes would benefit greatly by β-cell therapy. However, the paucity of available islets for transplantation as well as the immunological barriers faced in allogeneic transplantation represent a tremendous barrier to regene ...

Stem cells are present in all tissues and organs, and are crucial for normal regulated growth. How the pool size of stem cells and their progeny is regulated to establish the tissue prenatally, then maintain it throughout life, is a key question in biology and medicine. The ability to precisely locate s ...

Researchers interested in studying RNA structure and function or RNA-protein interactions are increasingly using site-specifically modified RNAs to probe sites of interest (1). In addition to expanding the repertoire of functional groups beyond the very limited set available th ...

A large number of genes express multiple mRNAs that encode diverse protein isoforms via alternative pre-mRNA splicing. For many genes, alternative splicing is regulated according to cell-specific patterns (in this chapter, cell-specific is used as a general term to refer to regulation a ...

The spliceosome is a large ribonucleoprotein that splices precursor messenger RNA (pre-mRNA) in the nuclei of eukaryotic cells (reviewed in refs. 1–3). It is composed of five small nuclear ribonucleoproteins (snRNPs) and numerous non-snRNP proteins. Each snRNP consists of a small nucle ...

Spliceosomes are multicomponent enzymes that remove introns from premessenger RNAs (pre-mRNAs) (1–3) in the reaction known as pre-mRNA splicing. Spliceosomes are ribonucleoprotein (RNP) machines consisting of both RNA and protein components. SnRNPs, composed of small nuclear ...

Splicing of eukaryotic precursor messenger RNAs (pre-mRNAs) excises the intron from the precursor and ligates the two exons together to produce the mature mRNA. It occurs via a two-step mechanism (Fig. 1) (reviewed in ref. 1). In the first step the 2′ hydroxyl group of an intronic adenylyl residue init ...

Splicing reactions are typically carried out using nuclear extracts, S100 extracts complemented with SR proteins, or partially purified fractions derived from the crude extracts. The extract preparation procedures are described in Chapter 24. Extracts derived from HeLa cells are ...

Following the initial discovery of split genes in 1977, it took several years before in vitro systems were successfully developed to study the biochemistry of pre-mRNA splicing. The first systems relied on coupling of transcription and splicing in whole-cell extracts and were fairly inef ...

Iterative selection strategies have been widely used to enrich specific RNA molecules from randomized pools based on binding affinities or an RNA-mediated activity (6,8). The vast majority of these procedures have been performed in cell-free systems. Of particular use would be iterati ...

Meiotic recombination is triggered by programmed DNA double-strand breaks (DSBs), which are catalyzed by Spo11 protein in a type II topoisomerase-like manner. Meiotic DSBs can be detected directly using physical assays (gel electrophoresis, Southern blotting, and indirect end-l ...