... feedback inhibition controls neoblast differentiation to regulate reversible growth of the planarian brain . Development 142 , 4217 - 4229 . Hill , E. M. and Petersen , C. P. ( 2018 ). Positional information specifies the site of organ regeneration and not tissue maintenance...

..., we show that Sonic hedgehog (Shh) signalling in the embryonic chick wing bud specifies positional information required for the formation of adult flight feathers in a defined spatial and temporal sequence that reflects their different identities. We also reveal that Shh signalling is interpreted...

...James Sharpe ABSTRACT Two phrases attributed to Lewis Wolpert – ‘positional information’ and ‘The French Flag Model’ – have become so intertwined that they are now used almost interchangeably. Here, I argue that this represents an unfortunate oversimplification of Wolpert's ideas that arose...

...Daniel Čapek; Patrick Müller ABSTRACT In order to contribute to the appropriate tissues during development, cells need to know their position within the embryo. This positional information is conveyed by gradients of signaling molecules, termed morphogens, that are produced in specific regions...

...-diffusion (RD)-based computational model and observed that the self-organization of pSMAD1 signaling was consistent with the RD principle. Consequent fate acquisition occurred as a function of both pSMAD1 signaling strength and duration of induction, consistent with the positional-information (PI) paradigm...

.... Highlighted Article: In the chick wing, the relative timing of the specification of antero-posterior positional values and self-organising mechanisms determines digit patterning and identity. Digits Limb Positional information Self-organization Shh Chick development Various models have...

... the first adult type hematopoietic stem cells(HSCs). The ventral position of hematopoietic clusters closely associated with the aorta of most vertebrate embryos suggests a polarity in the specification of AGM HSCs. Since positional information plays an important role in the embryonic development of several...

... Fat within each ommatidium. In this report, I test and confirm the key predictions of this model by altering the patterns of Fj, Ds and Fat expression. It is shown that the gradients of Fj and Ds expression provide partially redundant positional information essential for specifying the polarization...

... homeoprotein may directly regulate the expression of most genes. * Author for correspondence (e-mail: [email protected] ) 08 09 1998 20 10 1998 © 1998 by Company of Biologists 1998 Drosophila melanogaster Homeoproteins Homeotic genes Pair-rule genes Positional...

...Jeroen Charité; Wim de Graaff; Dimitri Consten; Mark J. Reijnen; Jeroen Korving; Jacqueline Deschamps ABSTRACT Studies of pattern formation in the vertebrate central nervous system indicate that anteroposterior positional information is generated in the embryo by signalling gradients of an as yet...

... expression of segmentation genes within the abdominal region of the embryo. In this study, we present evidence that kni and knrl link A/P positional information in larval wing imaginal discs to morphogenesis of the second longitudinal wing vein (L2). We show that kni and knrl are expressed in similar narrow...

... and Schiefelbein, 1996 ), the contribution of hormones to positional information in embryos is less clear. In Phaseolus vulgaris , gibberellins produced by the suspensor enhance transcription in the embryo proper (Walthall and Brady, 1986). More significantly, the effects of polar auxin transport inhibitors...

... of Biology, Carleton College, Northfield, MN 55057-4000, USA * Author for correspondence 4 September 1997 © 1997 by Company of Biologists 1997 Arabidopsis flower development ETTIN positional information Fig. 3. In situ hybridization detection of ETT...

... of stochastically forming sectors of valve tissue abutting style cells abutting stigmatic cells, suggests that a positional information mechanism exists for juxtaposing these cell types, and that ETT is involved in polarizing this information in one direction. Besides its role in global patterning, the data...

.... To ascertain the role of positional information in the axial patterning of LOX2 expression, we performed focal cell ablations that displaced one or another of the teloblast lineages out of segmental register with the other axial tissues. Such displacements brought about a corresponding shift in the LOX2...

... ). One way to conceptualize the patterning of the limb is in terms of positional information. Applying this framework to regeneration, there is a continuum of positional values extending along the length of the proximodistal axis from the shoulder to the tips of the fingers, distal values being lost...

... 31 08 1992 © 1992 by Company of Biologists 1992 methylation muscle myosin light chain positional information rostrocaudal gradient transgene Early in embryogenesis, spatially regulated patterns of gene expression establish systems of positional information that eventually...

... guidance. However, it is also possible that these transient gradients are markers of positional information that are important in other developmental events such as leg segmentation. We thank Robert Caldwell for performing the immunohisto-chemistry on frozen sections of tissue. This research was sup...

... that ultimately reconstituted the embryonic axis. © 1991 by Company of Biologists 1991 pattern formation positional information regeneration somatic embryogenesis Daucus carota Observing regeneration following the surgical removal of body parts is one of the oldest strategies for learning...

..., with the number of labeled glial cells varying with retinal position. * Current address: Memorial Sloan Kettering, New York, USA † Author for correspondence © 1991 by Company of Biologists 1991 positional information retinoic acid aldehyde dehydrogenase eye retina optic axons Müller...