E Boncinelli

..The existence of an ancestral complex locus might have predated the divergence of vertebrates and invertebrates...

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..Taken together, our data support the hypothesis that anteriorly expressed Hox genes might play a role in the refinement of the Otx2 early expression boundaries in vivo...

..Some of the DNA-protein complexes formed by the embryonic extracts are indistinguishable from those generated by HOXB3.(ABSTRACT TRUNCATED AT 250 WORDS)..

..The sequences on the HOX3D promoter involved in cross-regulation are different from those binding nuclear factors induced by RA...

..Microinjected transcripts of Xotx2 constructs containing a homeodomain where this lysine is substituted by a glutamine or a glutamic acid residue fail to cause these effects...

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..In addition, restricted defects along the rostrocaudal and the mediolateral axes are present in the subplate, suggesting an Emx2-specific role in priming the proper development of this layer...

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..The graded distribution of EMX2 homeoprotein suggests a potential role for Emx2 in the subdivision of the cortex into territories and possibly areas...

..The structural organization and the regulation of these genes appear remarkably conserved in evolution...

..We found that the normal spectrum of cortical areal identities was encoded in these mutants, but areas with caudal-medial identities were reduced and those with anterior-lateral identities were relatively expanded in the cortex...

..5). It is tempting to speculate about a possible role of the four genes in establishing and/or signalling the limits of the various embryonic brain regions in a discrete progressive process with its center in the dorsal telencephalon...

..Furthermore, there is evidence that Otx2 coordinates the activity of unrelated genes that have overlapping functions, and that it does so directly without intermediate transcriptional or signaling activity...

..Its gene product contains a homeodomain of the bicoid class and is able to recognize and transactivate a bicoid target sequence...

..These data suggest that Otx2 might be involved in defining local substrata for axon extension in the forebrain...

..XclpH3 is a Xenopus homologue of the mammalian calponin gene, the product of which binds both actin and myosin and prevents the generation of contractile force by actin filaments...

..those of the hair matrix of the caudal pelage hair follicles. Taken together, these observations strengthen the hypothesis that different homeobox gene families specify the regional identity of the skin in the cephalic and body regions...

..We have identified for the first time a homeogene of a different class at a HOX locus. These findings are relevant to the understanding of the evolution of HOX gene clusters and their regulation...

..The early expression and the nucleolar localization suggest an involvement of HOXC4 in the regulation of genes controlling lymphocyte activation and/or proliferation...

..These findings show that the caudal limit of Otx2 expression is sufficient for positioning the isthmic organizer and encoding caudal midbrain fate within the mid/hindbrain domain...

..In the developing neural retina, cSix3 is expressed in the entire undifferentiated neuroepithelium but is rapidly downregulated, first in the postmitotic photoreceptors and later in the majority of retinal ganglion cells...

..Homologies between forebrain subdivisions are proposed based on the conservation and divergence of these gene expression patterns...

..1). 7 mouse strains, namely 129, BALB/c, C57BL/6, C57BL/10, CAST/Ei, C3H and SPRET/Ei, are homozygous for this allele. The allele present in gibbon and rhesus monkey appears to be identical to the human HOXB1b (Fig. 1)...

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..Our data and the genetic interactions previously documented in the nematode suggest that Mab21 may represent a novel, important regulator of mammalian cerebellum and eye development...

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..The expression of other developmentally relevant genes such as pax(zf-a), pax(zf-b) and krx-20 was not affected in the antisense treated embryos...

..6 gene and the expression of transgenic and endogenous transcripts in a Hox-2.8 pattern, suggest that regulatory elements may be shared by neighbouring genes to establish the complete expression pattern...

..8 is expressed in more posterodistal regions than those of its neighbour Hox-4.7. Hence, Hox-4.8 expression appears to be related to the last significant phenotypic changes towards the extremities of the embryonic body and limb axes...

..Together, the results of the embryonic/fetal expression of c1 and c8 and those of two previously analyzed genes (c10 and c13) indicate a coherent pattern of expression of these genes in early human ontogeny...

..Neither of the class I homeo box-containing genes--c8 and c13--maps to a region of obvious homology to chromosomal positions of the presently known mouse homeo box-containing genes...

..A major polyadenylated transcript of approximately 2.1 kilobases (kb), as well as RNA species of higher relative molecular mass (Mr), are specifically expressed at a constant level in spinal cord throughout this developmental period...

..We speculate that the repressor function of EVX1 contributes to its proposed role in embryogenesis...

..The functional significance of the nucleolar localisation of Hox proteins remains to be determined...

..However, the HOX C8 transcript pattern is lineage specific. These data, in conjunction with earlier findings, suggest that homeobox gene expression influences lineage determination during hematopoiesis...

..The protein is present in axons of olfactory sensory neurons along their entire length, including their terminals in spherical regions of neuropil in the olfactory bulb called glomeruli...

..These findings demonstrate that Emx2 is required for the development of several forebrain structures...

..Emx1 is expressed exclusively there, whereas Emx2 is also expressed in some neuroectodermal areas in embryonic head including olfactory placodes in earlier stages and olfactory epithelia later in development...