Home About us Contact
|
Home About us Contact | ||
|
|
||
Organ Formation (organ + formation)
Selected AbstractsThe CLAVATA1-related BAM1, BAM2 and BAM3 receptor kinase-like proteins are required for meristem function in ArabidopsisTHE PLANT JOURNAL, Issue 1 2006Brody J. DeYoung Summary Organ formation at shoot and flower meristems in plants requires the maintenance of a population of centrally located stem cells and the differentiation of peripherally located daughter cells. The CLAVATA (CLV) gene products in Arabidopsis, including the CLV1 receptor-kinase, regulate this process by promoting the differentiation of stem cells on the meristem flanks. Here, we have analyzed the developmental roles of the CLV1-related BAM1 (derived from barely any meristem 1), BAM2 and BAM3 receptor-like kinases. Loss-of-function alleles of these receptors lead to phenotypes consistent with the loss of stem cells at the shoot and flower meristem, suggesting that their developmental role is opposite to that of CLV1. These closely related receptors are further distinguished from CLV1, whose expression and function is highly specific, by having broad expression patterns and multiple developmental roles. These include a requirement for BAM1, BAM2 and BAM3 in the development of high-ordered vascular strands within the leaf and a correlated control of leaf shape, size and symmetry. In addition, BAM1, BAM2 and BAM3 are required for male gametophyte development, as well as ovule specification and function. Significantly, the differing roles of CLV1 and BAM receptors in meristem and organ development are largely driven by differences in expression patterns. [source] Transcriptional dynamics of endodermal organ formationDEVELOPMENTAL DYNAMICS, Issue 1 2009Richard I. Sherwood Abstract Although endodermal organs including the liver, pancreas, and intestine are of significant therapeutic interest, the mechanism by which the endoderm is divided into organ domains during embryogenesis is not well understood. To better understand this process, global gene expression profiling was performed on early endodermal organ domains. This global analysis was followed up by dynamic immunofluorescence analysis of key transcription factors, uncovering novel expression patterns as well as cell surface proteins that allow prospective isolation of specific endodermal organ domains. Additionally, a repressive interaction between Cdx2 and Sox2 was found to occur at the prospective stomach,intestine border, with the hepatic and pancreatic domains forming at this boundary, and Hlxb9 was revealed to have graded expression along the dorsal,ventral axis. These results contribute to understanding the mechanism of endodermal organogenesis and should assist efforts to replicate this process using pluripotent stem cells. Developmental Dynamics 238:29,42, 2009. © 2008 Wiley-Liss, Inc. [source] Second chromosome genes required for heart development in Drosophila melanogasterGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 10 2007Ye Tao Abstract Heart development is an evolutionarily conserved process. The cardiac organ of Drosophila melanogaster is the dorsal vessel, a linear contractile tissue with cellular and morphogenetic similarities to the primitive heart tube formed at an early stage of vertebrate heart formation. Abundant evidence shows comparable intercellular signaling pathways and transcription factor networks are utilized in Drosophila and vertebrates, to specify cardiac progenitor cells and instruct their differentiation and function in forming the mature heart. With this proven conservation in mind, we screened the second chromosome of Drosophila for genetic intervals that harbor additional loci required for normal dorsal vessel morphogenesis. Our studies identified numerous regions, that when deleted, culminated in dorsal vessels with abnormal cell numbers and/or structural properties. Certain of the deficiency intervals were further characterized to identify individual genes essential for proper cardiac organ formation. Our analyses identified eight genes of diverse functions that are needed for dorsal vessel development. Several of these sequences have known vertebrate homologues, further supporting a conserved genetic basis for heart formation in Drosophila and higher eukaryotes. genesis 45:607,617, 2007. © 2007 Wiley-Liss, Inc. [source] Contribution of endothelial cells to organogenesis: a modern reappraisal of an old Aristotelian conceptJOURNAL OF ANATOMY, Issue 4 2007E. Crivellato Abstract It is well established that many tissue-derived factors are involved in blood vessel formation, but evidence is now emerging that endothelial cells themselves represent a crucial source of instructive signals to non-vascular tissue cells during organ development. Thus, endothelial cell signalling is currently believed to promote fundamental cues for cell fate specification, embryo patterning, organ differentiation and postnatal tissue remodelling. This review article summarizes some of the recent advances in our understanding of the role of endothelial cells as effector cells in organ formation. [source] Actively regulating bioengineered tissue and organ formationORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2005DJ Mooney Structured Abstract Authors ,, Mooney DJ, Boontheekul T, Chen R, Leach K Objectives ,, Describe current and future approaches to tissue engineering, specifically in the area of bone regeneration. These approaches will allow one to actively regulate the cellular populations participating in this process. Design ,, Many approaches to actively regulate cellular phenotype are under exploration, and these typically exploit known signal transduction pathways via presentation of specific receptor-binding ligands, and may also deliver mechanical information via the physical bridge formed by the receptor-ligand interactions. Cellular gene expression may also be directly modulated utilizing gene therapy approaches to control tissue regeneration. Conclusions ,, Significant progress has been made to date in bone regeneration using inductive molecules and transplanted cells, and FDA approved therapies have resulted. While approaches to date have focused on delivery of single stimuli (e.g. one growth factor), future efforts will likely attempt to more closely mimic developmental processes by the delivery of multiple inputs to the cells in spatially and temporally regulated fashions. [source] | ||||||||||