Isolation, molecular cloning and in vitro expression of rhesus monkey (Macaca mulatta) prominin-1.s1 complementary DNA encoding a potential hematopoietic stem cell antigen

Goldfish (Carassius auratus L.) as a model system to study the growth factors, receptors and transcription factors that govern myelopoiesis in fish

The process of myeloid cell development (myelopoiesis) in fish has mainly been studied in three cyprinid species: zebrafish (Danio rerio), ginbuna carp (Carassius auratus langsdorfii) and goldfish (C. auratus, L.). Our studies on goldfish myelopoiesis have utilized in vitro generated primary kidney macrophage (PKM) cultures and isolated primary kidney neutrophils (PKNs) cultured overnight to study the process of macrophage (monopoiesis) and neutrophil (granulopoiesis) development and the key growth factors, receptors, and transcription factors that govern this process in vitro. The PKM culture system is unique in that all three subpopulations of macrophage development, namely progenitor cells, monocytes, and mature macrophages, are simultaneously present in culture unlike mammalian systems, allowing for the elucidation of the complex mixture of cytokines that regulate progressive and selective macrophage development from progenitor cells to fully functional mature macrophages in vitro. Furthermore, we have been able to extend our investigations to include the development of erythrocytes (erythropoiesis) and thrombocytes (thrombopoiesis) through studies focusing on the progenitor cell population isolated from the goldfish kidney. Herein, we review the in vitro goldfish model systems focusing on the characteristics of cell sub-populations, growth factors and their receptors, and transcription factors that regulate goldfish myelopoiesis.

CD133: molecule of the moment

CD133 (prominin-1) was the first in a class of novel pentaspan membrane proteins to be identified in both humans and mice, and was originally classified as a marker of primitive haematopoietic and neural stem cells. Due to the highly restricted expression of CD133 family molecules on plasma membrane protrusions of epithelial and other cell types, in association with membrane cholesterol, a role in the organization of plasma membrane topology has also recently been assigned to this family. Studies have now confirmed the utility of CD133 as a marker of haematopoietic stem cells for human allogeneic transplantation. In addition, CD133 represents a marker of tumour-initiating cells in a number of human cancers, and therefore it may be possible to develop future therapies towards targeting cancer stem cells via this marker. The development of such therapies will be aided by a clearer understanding of the molecular mechanisms and signalling pathways that regulate the behaviour of CD133-expressing cells, and new data outlining the role of Wnt, Notch, and bone morphogenetic protein (BMP) signalling in CD133(+) cancer stem cell regulation are discussed within.

Nomenclature of prominin-1 (CD133) splice variants - an update

Prominin-1 (CD133), a pentaspan membrane glycoprotein that constitutes an important cell surface marker of various, either normal or cancerous, stem cell populations is widely used to isolate or characterize such cells in different systems. Occurring throughout the metazoan evolution with a remarkably conserved genomic organization, it may be expressed as different splice variants with distinctive characteristics. A rational nomenclature has been proposed earlier for their consistent designation across species. Although generally accepted, it seems to be misunderstood in view of the recent report of novel prominin-1 complementary DNAs in rhesus monkey and humans with improper naming. As this may lead to confusion, we have reexamined the genomic organization of prominin-1 in various primates to provide an update that should further clarify the rationale of the nomenclature for prominin-1 gene products. This report comprises (i) the determination of the genomic organization of prominin-1 gene in two non-human primates, i.e. Macaca mulatta and Pan troglodytes, commonly used in research, (ii) the mapping of a new exon that creates an alternative cytoplasmic C-terminal end of prominin-1, (iii) the identification of various potential PDZ-binding domains generated by alternative cytoplasmic C-terminal tails, suggesting that different prominin-1 splice variants might interact with distinct protein partners, and (iv) a summing up of the different prominin-1 splice variants.