Reprogramming of Human Fibroblasts with Non-integrating RNA Virus on Feeder-Free or Xeno-Free Conditions.

Recent advances in generating induced pluripotent stem cells have radically advanced the field of regenerative medicine by making possible the production of patient-specific pluripotent stem cells from somatic cells. However, a major obstacle to the use of iPSC for therapeutic applications is the potential genomic modifications resulted from viral insertion of transgenes in the cellular genome. Second, the culture of iPSCs and adult cells often requires the use of animal products, which hinder the generation of clinical-grade iPSCs.

Profiling stem cells using quantitative PCR protein assays.

Reprogramming human somatic cells to induced pluripotent stem cells is an important avenue in biological research. Advances in the profiling of human stem cells have identified important pluripotency maintenance factors. The presence and relative expression levels of these essential markers are commonly used to define the pluripotency status and potential of reprogrammed stem cells.

Generation of human-induced pluripotent stem cells (hiPSCs) using episomal vectors on defined Essential 8™ Medium conditions.

Human-induced pluripotent stem cells (iPSCs) are an important potential source of cells for regenerative medicine due to their inherent ability to differentiate into all cell types of the three germ layers. Generation of iPSCs with a non-integrating reprogramming method and in culture conditions that are completely absent of animal proteins will be ideal for such regenerative and cell therapy applications. Here we describe a method to generate non-integrating iPSCs using the Episomal iPSC Reprogramming Vectors.

Generation of induced pluripotent stem cells with CytoTune, a non-integrating Sendai virus.

One of the major obstacles in generating induced pluripotent stem cells for research or downstream applications is the potential modifications of cellular genome as a result of using integrating viruses during reprogramming. Another major disadvantage of reprogramming cells with integrating vectors is that silencing and activation of transgenes are unpredictable, which may affect terminal differentiation potential and increase the risk of using iPSC-derived cells. Here we describe a protocol for the generation of induced pluripotent stem cells using a non-integrating RNA virus, Sendai virus, to efficiently generate transgene-free iPSCs starting with different cell types as well as in feeder-free conditions.

Generation of human-induced pluripotent stem cells by a nonintegrating RNA Sendai virus vector in feeder-free or xeno-free conditions.

The generation of induced pluripotent stem cells (iPSCs) from somatic cells has enabled the possibility of providing unprecedented access to patient-specific iPSC cells for drug screening, disease modeling, and cell therapy applications. However, a major obstacle to the use of iPSC for therapeutic applications is the potential of genomic modifications caused by insertion of viral transgenes in the cellular genome. A second concern is that reprogramming often requires the use of animal feeder layers and reagents that contain animal origin products, which hinder the generation of clinical-grade iPSCs.

Applications of quantitative polymerase chain reaction protein assays during reprogramming.

The capability to reprogram human somatic cells to induced pluripotent stem cells (iPSCs) has opened a new area of biology and provides unprecedented access to patient-specific iPSCs for drug screening, disease models, and transplantation therapies. Although the process of obtaining iPSC lines is technically simple, reprogramming is a slow and inefficient process consisting of a largely uncharacterized chain of molecular events. To date, researchers have reported a wide range of reprogramming efficiencies, from <0.

Expanding applications of protein analysis using proximity ligation and qPCR.

The correlation of gene and protein expression changes in biological systems has been hampered by the need for separate sample handling and analysis platforms for nucleic acids and proteins. In contrast to the simple, rapid, and flexible workflow of quantitative PCR (qPCR) methods, which enable characterization of several classes of nucleic acid biomarkers (i.e.

Generation of site-specific retargeting platform cell lines for drug discovery using phiC31 and R4 integrases.

One of the challenges in developing cell lines for high-throughput screening in drug discovery is the labor- and time-intensive process required to create stable clonal cell lines that express specific reporters or drug targets. The authors report here the generation of a site-specific retargeting platform in 3 different cell lines: adherent HEK293, suspension CHO-S, and a human embryonic cell line (BGO1V). These platform cell lines were generated by using a combination of 2 site-specific integrases to develop a system that allows one to efficiently target a gene of interest to a specific locus and generates rapid production of homogeneous cell pools that stably express the gene of interest.

Generation of platform human embryonic stem cell lines that allow efficient targeting at a predetermined genomic location.

Bacteriophage recombinases can target specific loci in human embryonic stem cells (hESCs) at high efficiency, allowing for long-term expression of transgenes. In the present work, we describe a retargeting system where we used phiC31 integrase to target a plasmid to a pseudo-attP site in the cellular genome. The integration site was mapped and the chromosomal location evaluated for potential to be transcriptionally active in differentiated cells.

Development of a DNA-labeling system for array-based comparative genomic hybridization.

Chromosomal amplifications and deletions are critical components of tumorigenesis and DNA copy-number variations also correlate with changes in mRNA expression levels. Genome-wide microarray comparative genomic hybridization (CGH) has become an important method for detecting and mapping chromosomal changes in tumors. Thus, the ability to detect twofold differences in fluorescent intensity between samples on microarrays depends on the generation of high-quality labeled probes.

Altering the expression kinetics of VP5 results in altered virulence and pathogenesis of herpes simplex virus type 1 in mice.

While many herpes simplex virus (HSV) structural proteins are expressed with strict-late kinetics, the HSV virion protein 5 (VP5) is expressed as a "leaky-late" protein, such that appreciable amounts of VP5 are made prior to DNA replication. Our goal has been to determine if leaky-late expression of VP5 is a requirement for a normal HSV infection. It had been shown previously that recombinant viruses in which the VP5 promoter was replaced with promoters of other kinetic classes (including a strict late promoter) exhibited no alterations in replication kinetics or virus yields in vitro.