PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 7646887

Systematic widespread clonal organization in cerebral cortex.

C B Reid·I Liang·C Walsh
View original source ↗Export metadata ↓

Abstract

Cell lineage analysis in the cortex has revealed two clonal patterns, clustered and widespread clones. To determine the relationship of these patterns, progenitor cells were infected with a retroviral library encoding alkaline phosphatase, and cortical sibling cells were identified using PCR. Clones labeled at E15 consisted of single cells or small cells clusters (52%) or of widespread cells (48%). However, widespread clones consisted of multiple neuronal or glial cell types, spaced systematically at 2-3 mm intervals. The data suggest that migratory multipotential progenitors divide asymmetrically at intervals defined by cell cycle length, producing single cells or clusters of cells in different cortical regions. Transition from multipotentiality to more restricted potential may correspond to changes in migratory behavior.

Explore related subjects

Alkaline PhosphataseAnimalsBiomarkersCell CountCell CycleCell DivisionCell MovementCerebral CortexClone CellsComputer SimulationDNA, ViralGene LibraryGenetic VectorsModels, NeurologicalMonte Carlo MethodMorphogenesisNeurogliaNeuronsPolymerase Chain ReactionRatsRetroviridaeStem CellsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C B Reid, I Liang, C Walsh. 1995. Systematic widespread clonal organization in cerebral cortex.. https://doi.org/10.1016/0896-6273(95)90035-7

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2024

A distinct, high-affinity, alkaline phosphatase facilitates occupation of P-depleted environments by marine picocyanobacteria.

Marine picocyanobacteria of the genera Prochlorococcus and Synechococcus, the two most abundant phototrophs on Earth, thrive in oligotrophic oceanic regions. While it is well known that specific lineages are exquisitely adapted to prevailing in situ light and temperature regimes, much less is known of the molecular machinery required to facilitate occupancy of these low-nutrient environments. Here, we describe a hitherto unknown alkaline phosphatase, Psip1, that has a substantially higher affinity for phosphomonoesters than other well-known phosphatases like PhoA, PhoX, or PhoD and is restricted to clade III Synechococcus and a subset of high light I-adapted Prochlorococcus strains, suggesting niche specificity. We demonstrate that Psip1 has undergone convergent evolution with PhoX, requiring both iron and calcium for activity and likely possessing identical key residues around the active site, despite generally very low sequence homology. Interrogation of metagenomes and transcriptomes from TARA oceans and an Atlantic Meridional transect shows that psip1 is abundant and highly expressed in picocyanobacterial populations from the Mediterranean Sea and north Atlantic gyre, regions well recognized to be phosphorus (P)-deplete. Together, this identifies psip1 as an important oligotrophy-specific gene for P recycling in these organisms. Furthermore, psip1 is not restricted to picocyanobacteria and is abundant and highly transcribed in some α-proteobacteria and eukaryotic algae, suggesting that such a high-affinity phosphatase is important across the microbial taxonomic world to occupy low-P environments.

Alkaline Phosphatase↗
PubMed2007

High cell density fed batch and perfusion processes for stable non-viral expression of secreted alkaline phosphatase (SEAP) using insect cells: comparison to a batch Sf-9-BEV system.

The development of insect cells expressing recombinant proteins in a stable continuous manner is an attractive alternative to the BEV system for recombinant protein production. High cell density fed batch and continuous perfusion processes can be designed to maximize the productivity of stably transformed cells. A cell line (Sf-9SEAP) expressing high levels of the reporter protein SEAP stably was obtained by lipid-mediated transfection of Sf-9 insect cells and further selection and screening. The expression of the Sf-9SEAP cells was compared with the BEVS system. It was observed that, the yield obtained in BEVS was similar to the batch Sf-9SEAP at 8 and 7 IU/mL, respectively. The productivity of this foreign gene product with the stable cells was enhanced by bioprocess intensification employing the fed-batch and perfusion modes of culture to increase the cell density in culture. The fed batch process yielded a maximum cell density of 28 x 10(6) cells/mL and 12 IU/mL of SEAP. Further improvements in the productivity could be made using the perfusion process, which demonstrated a stable production rate for extended periods of time. The process was maintained for 43 days, with a steady-state cell density of 17-20 x 10(6) cells/mL and 7 IU/mL SEAP. The total yield obtained in the perfusion process (394 IU) was approximately 22 and 8 times higher than that obtained in a batch (17.6 IU) and fed batch (46.1 IU) process, respectively.

Alkaline Phosphatase↗
PubMed2007

The addition of biphasic calcium phosphate to porous chitosan scaffolds enhances bone tissue development in vitro.

Uniform distribution of cells and their extracellular matrix is essential for the in vivo success of bone tissue engineering constructs produced in vitro. In this study, the effects of biphasic calcium phosphate (BCP) granules embedded into chitosan scaffolds on the distribution, morphology, and phenotypic expression of osteoblastic cells were investigated. Mesenchymal stem cells (MSCs) and preosteoblasts were cultured on chitosan scaffolds with and without BCP under osteoblastic differentiation/maturation conditions for periods up to 4 weeks. The addition of 25 wt % BCP to chitosan created a uniform layer of calcium phosphate (CaP) precipitation similar to bone mineral on the scaffold surfaces as determined by scanning electron microscopy and X-ray spectroscopy. Scaffolds with this CaP layer yielded more uniform and complete cell and ECM distribution than chitosan scaffolds without BCP. The suggestion of chemotaxis in the appearance of this response was confirmed by successive experiments in a Boyden chamber. The CaP layer also altered morphology of cells initially attached to the scaffold surfaces, leading to higher expression of marker proteins of osteoblastic phenotype including alkaline phosphatase and osteocalcin. The use of chitosan/BCP scaffolds for culture of MSCs and preosteoblasts enhances bone tissue development in vitro.

Alkaline Phosphatase↗