Transcription factor induction of vascular blood stem cell niches in vivo

The hematopoietic niche is a supportive microenvironment composed of distinct cell types, including specialized vascular endothelial cells that directly interact with hematopoietic stem and progenitor cells (HSPCs). The molecular factors that specify niche endothelial cells and orchestrate HSPC homeostasis remain largely unknown. Using multi-dimensional gene expression and chromatin accessibility analyses in zebrafish, we define a conserved gene expression signature and cis-regulatory landscape that are unique to sinusoidal endothelial cells in the HSPC niche. Using enhancer mutagenesis and transcription factor overexpression, we elucidate a transcriptional code that involves members of the Ets, Sox, and nuclear hormone receptor families and is sufficient to induce ectopic niche endothelial cells that associate with mesenchymal stromal cells and support the recruitment, maintenance, and division of HSPCs in vivo. These studies set forth an approach for generating synthetic HSPC niches, in vitro or in vivo, and for effective therapies to modulate the endogenous niche

Executive Incentive Schemes in Initial Public Offerings: The Effects of Multiple-Agency Conflicts and Corporate Governance

Combining a behavioral agency perspective with research on multiple-agency conflicts, this article examines factors affecting the implementation of equity-based incentive schemes in initial public offerings (IPOs). With a unique sample of U.K. IPO companies between the years 1998 and 2002, it shows that conditional (performance-related) incentive schemes are negatively associated with share ownership and board power of the IPO’s founding directors. However, the retained ownership of venture capital firms is positively associated with the probability of conditional incentive schemes. Board independence weakly effects on the toughness of executive compensation. The article’s interesting findings suggest a number of avenues for a future analysis of the governance development process in threshold firms

Board diversity in the United Kingdom and Norway : an exploratory analysis

This paper examines the evolving pattern of gender diversity of the boards of directors of leading Norwegian and British companies on a longitudinal basis. The period covered by the study covers the run up to proposed affirmative action legislation in Norway and, as such, affords an insight into corporate actions in this emerging institutional context. The findings demonstrate that, while board diversity has grown substantially in both countries in recent years, it has done so considerably more rapidly in Norway than in the United Kingdom. The analysis highlights the sectoral variation between the countries in the pattern and growth of board diversity and suggests that the vast majority of the overall growth in board diversity is the result of changing firm behaviour rather than sectoral shift in the United Kingdom or Norwegian economies. It is also shown that as diversity has increased there has been no fall in how experienced female directors are; neither is there evidence of a rise in the number of boards that female directors sit on. This suggests that the rapid growth in board diversity has been achieved without any fall in the quality of female directors.14 page(s