Home About us Contact
|
Home About us Contact | ||
|
|
||
Differentiation Program (differentiation + program)
Selected AbstractsExpression of WASP and Scar1/WAVE1 actin-associated proteins is differentially modulated during differentiation of HL-60 cellsCYTOSKELETON, Issue 4 2003Sophie Launay Abstract The Wiskott-Aldrich Syndrome (WAS) is a disease associated with mutations in the WAS gene and characterised by developmental defects in haematopoietic cells such as myeloid cells. The Wiskott-Aldrich Syndrome protein (WASP)-family includes Scar1 and WASP, which are key regulators of actin reorganization in motile cells. To understand the roles of Scar1 and WASP in myeloid cells and their cytoskeletal control in haematopoietic tissues, we have explored their expression during differentiation of the promyeloid cell line HL-60. Undifferentiated HL-60 cells expressed Scar1 and WASP, and differentiation to neutrophils, induced by retinoic acid or non-retinoid agent treatments, led to a decrease in the level of expression of Scar1, whereas WASP expression was unaffected. Differentiation to monocytes/macrophages, induced by phorbol ester treatment, resulted in a decreased expression of both proteins in the adherent mature cells. Vitamin D3 treatment or cytochalasin D in combination with PMA treatment did not affect WASP expression suggesting that adhesion and cytoskeletal integrity were both essential to regulate WASP expression. Scar1 expression was regulated by differentiation, adhesion, and cytoskeletal integrity. Recently, WASP was found to colocalize with actin in the podosomes. In contrast, we show here that Scar1 did not localize with the podosomes in mature monocytes/macrophages. These observations show for the first time that modulation of Scar1 and WASP expression is a component of the differentiation program of myeloid precursors and indicate that WASP and Scar1 have different roles in mature myeloid cells. Cell Motil. Cytoskeleton 54:274,285, 2003. © 2003 Wiley-Liss, Inc. [source] Thymic generation and regenerationIMMUNOLOGICAL REVIEWS, Issue 1 2003Jason Gill Summary:, The thymus is a complex epithelial organ in which thymocyte development is dependent upon the sequential contribution of morphologically and phenotypically distinct stromal cell compartments. It is these microenvironments that provide the unique combination of cellular interactions, cytokines, and chemokines to induce thymocyte precursors to undergo a differentiation program that leads to the generation of functional T cells. Despite the indispensable role of thymic epithelium in the generation of T cells, the mediators of this process and the differentiation pathway undertaken by the primordial thymic epithelial cells are not well defined. There is a lack of lineage-specific cell-surface-associated markers, which are needed to characterize putative thymic epithelial stem cell populations. This review explores the role of thymic stromal cells in T-cell development and thymic organogenesis, as well as the molecular signals that contribute to the growth and expansion of primordial thymic epithelial cells. It highlights recent advances in these areas, which have allowed for a lineage relationship amongst thymic epithelial cell subsets to be proposed. While many fundamental questions remain to be addressed, collectively these works have broadened our understanding of how the thymic epithelium becomes specialized in the ability to support thymocyte differentiation. They should also facilitate the development of novel, rationally based therapeutic strategies for the regeneration and manipulation of thymic function in the treatment of many clinical conditions in which defective T cells have an important etiological role. [source] Sequential activation of transcription factors in lens inductionDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2000Hajime Ogino Since the pioneering work of the early 1900s, the lens has been used as a model system for the study of tissue development in vertebrates. A number of embryological transplantation experiments designed to elucidate the role of tissue interactions in the formation of the lens have led to the proposal of a stepwise determination model. This model has recently been refined through the identification of certain transcription factor genes, which exhibit distinct expression patterns and functional properties in the lens cell lineage. Otx2, Pax6, and Lens1 are induced by the adjacent anterior neural plate and expressed in predifferentiated lens ectoderm. Contact between the optic vesicle and lens ectoderm promotes expression of mafs, Soxs, and Prox1, which are responsible for the initiation of lens differentiation programs including crystallin expression, cell elongation, and cell cycle arrest. Further analysis of the expression and functional characteristics of these transcription factors will allow greater detail when describing the orchestration of genetic programs, which control tissue development from induction to maturation. [source] p63 in prostate biology and pathologyJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2008Chiara Grisanzio Abstract The identification of stem cells and differentiation programs regulating the development and maintenance of the normal prostate epithelium is essential for the identification of the cell type(s) and molecular alterations involved in the development and propagation of prostate cancer (CaP). The p53-homologue p63 is highly expressed in normal prostate basal cells and is a clinically useful biomarker for the diagnosis of CaP. Importantly, p63 has been shown to play a critical role in prostate development. Recent experimental evidence also suggests that this gene is essential for normal stem cell function in the prostate as well as other epithelial organs. Future studies aimed at better defining the role of p63 in the renewal of the adult prostate epithelium are likely to shed new light on the mechanisms involved in prostate carcinogenesis. J. Cell. Biochem. 103: 1354,1368, 2008. © 2007 Wiley-Liss, Inc. [source] | ||||||||||