scholarly journals Identification of Epha4 enhancer required for segmental expression and the regulation by Mesp2

Development ◽  
2006 ◽  
Vol 133 (13) ◽  
pp. 2517-2525 ◽  
Author(s):  
Y. Nakajima
Keyword(s):  
Segmental Expression

Conserved and distinct roles of kreisler in regulation of the paralogous Hoxa3 and Hoxb3 genes

Development ◽  
1999 ◽  
Vol 126 (4) ◽  
pp. 759-769 ◽  
Author(s):  
M. Manzanares ◽  
S. Cordes ◽  
L. Ariza-McNaughton ◽  
V. Sadl ◽  
K. Maruthainar ◽  
...  
Keyword(s):  
Binding Sites ◽  
Hox Genes ◽  
Expression Patterns ◽  
Regulatory Elements ◽  
Enhancer Activity ◽  
Anteroposterior Patterning ◽  
Endogenous Gene ◽  
Transgenic Embryos ◽  
The Individual ◽  
Segmental Expression

During anteroposterior patterning of the developing hindbrain, the anterior expression of 3′ Hox genes maps to distinct rhombomeric boundaries and, in many cases, is upregulated in specific segments. Paralogous genes frequently have similar anterior boundaries of expression but it is not known if these are controlled by common mechanisms. The expression of the paralogous Hoxa3 and Hoxb3 genes extends from the posterior spinal cord up to the rhombomere (r) 4/5 boundary and both genes are upregulated specifically in r5. However, in this study, we have found that Hoxa3 expression is also upregulated in r6, showing that there are differences in segmental expression between paralogues. We have used transgenic analysis to investigate the mechanisms underlying the pattern of segmental expression of Hoxa3. We found that the intergenic region between Hoxa3 and Hoxa4 contains several enhancers, which summed together mediate a pattern of expression closely resembling that of the endogenous Hoxa3 gene. One enhancer specifically directs expression in r5 and r6, in a manner that reflects the upregulation of the endogenous gene in these segments. Deletion analysis localized this activity to a 600 bp fragment that was found to contain a single high-affinity binding site for the Maf bZIP protein Krml1, encoded by the kreisler gene. This site is necessary for enhancer activity and when multimerized it is sufficient to direct a kreisler-like pattern in transgenic embryos. Furthermore the r5/r6 enhancer activity is dependent upon endogenous kreisler and is activated by ectopic kreisler expression. This demonstrates that Hoxa3, along with its paralog Hoxb3, is a direct target of kreisler in the mouse hindbrain. Comparisons between the Krml1-binding sites in the Hoxa3 and Hoxb3 enhancers reveal that there are differences in both the number of binding sites and way that kreisler activity is integrated and restricted by these two control regions. Analysis of the individual sites revealed that they have different requirements for mediating r5/r6 and dorsal roof plate expression. Therefore, the restriction of Hoxb3 to r5 and Hoxa3 to r5 and r6, together with expression patterns of Hoxb3 in other vertebrate species suggests that these regulatory elements have a common origin but have later diverged during vertebrate evolution.

Conserved segmental expression of Krox-20 in the vertebrate hindbrain and its relationship to lineage restriction

Development ◽  
1991 ◽  
Vol 113 (Supplement_2) ◽  
pp. 59-62 ◽  
Author(s):  
M. Angela Nieto ◽  
Leila C. Bradley ◽  
David G. Wilkinson
Keyword(s):  
Expression Pattern ◽  
Zinc Finger ◽  
Cell Lineage ◽  
Zinc Finger Gene ◽  
Early Stages ◽  
Cellular Events ◽  
Early Expression ◽  
Segmental Expression

The zinc-finger gene Krox-20 is expressed in two alternating segments, rhombomeres (r) 3 and 5, in the developing mouse hindbrain. This expression pattern is established prior to rhombomere formation in the mouse, but it is not known how the timing of expression relates to cellular events of segmentation, such as lineage restriction. We have cloned Krox-20 sequences from Xenopus and the chick and shown that its alternating expression pattern is conserved in these systems, suggesting that its role in hindbrain development is conserved. Analysis of the early stages of Krox-20 expression in the chick show that both domains of expression precede the restriction of cell lineage to specific rhombomeres, consistent with a role of this gene in early events of hindbrain segmentation. The finding that expression is not coincident with lineage restriction indicates that early expression may not reflect an irreversible commitment of cells to r3 and r5 and/or may be mosaic.

Discrete Polycomb-binding sites in each parasegmental domain of the bithorax complex

Development ◽  
1995 ◽  
Vol 121 (6) ◽  
pp. 1681-1689 ◽  
Author(s):  
A. Chiang ◽  
M.B. O'Connor ◽  
R. Paro ◽  
J. Simon ◽  
W. Bender
Keyword(s):  
Binding Sites ◽  
Polytene Chromosomes ◽  
Homeotic Genes ◽  
Bithorax Complex ◽  
Lacz Reporter Gene ◽  
Regulatory Regions ◽  
Cooperative Action ◽  
Polycomb Protein ◽  
Regulatory Dna ◽  
Segmental Expression

The Polycomb protein of Drosophila melanogaster maintains the segmental expression limits of the homeotic genes in the bithorax complex. Polycomb-binding sites within the bithorax complex were mapped by immunostaining of salivary gland polytene chromosomes. Polycomb bound to four DNA fragments, one in each of four successive parasegmental regulatory regions. These fragments correspond exactly to the ones that can maintain segmentally limited expression of a lacZ reporter gene. Thus, Polycomb acts directly on discrete multiple sites in bithorax regulatory DNA. Constructs combining fragments from different regulatory regions demonstrate that Polycomb-dependent maintenance elements can act on multiple pattern initiation elements, and that maintenance elements can work together. The cooperative action of maintenance elements may motivate the linear order of the bithorax complex.

The Notch ligand, X-Delta-2, mediates segmentation of the paraxial mesoderm in Xenopus embryos

Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1169-1178 ◽  
Author(s):  
W.C. Jen ◽  
D. Wettstein ◽  
D. Turner ◽  
A. Chitnis ◽  
C. Kintner
Keyword(s):  
Paraxial Mesoderm ◽  
Bhlh Gene ◽  
Presomitic Mesoderm ◽  
Notch 1 ◽  
Notch Ligand ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Vertebrate Embryo ◽  
Somite Formation ◽  
Segmental Expression

Segmentation of the vertebrate embryo begins when the paraxial mesoderm is subdivided into somites, through a process that remains poorly understood. To study this process, we have characterized X-Delta-2, which encodes the second Xenopus homolog of Drosophila Delta. Strikingly, X-Delta-2 is expressed within the presomitic mesoderm in a set of stripes that corresponds to prospective somitic boundaries, suggesting that Notch signaling within this region establishes a segmental prepattern prior to somitogenesis. To test this idea, we introduced antimorphic forms of X-Delta-2 and Xenopus Suppressor of Hairless (X-Su(H)) into embryos, and assayed the effects of these antimorphs on somite formation. In embryos expressing these antimorphs, the paraxial mesoderm differentiated normally into somitic tissue, but failed to segment properly. Both antimorphs also disrupted the segmental expression of X-Delta-2 and Hairy2A, a basic helix-loop-helix (bHLH) gene, within the presomitic mesoderm. These observations suggest that X-Delta-2, via X-Notch-1, plays a role in segmentation, by mediating cell-cell interactions that underlie the formation of a segmental prepattern prior to somitogenesis.

scholarly journals Shifting roles of Drosophila pair-rule gene orthologs: segmental expression and function in the milkweed bug Oncopeltus fasciatus

Development ◽  
2019 ◽  
Vol 146 (17) ◽  
pp. dev181453 ◽  
Author(s):  
Katie Reding ◽  
Mengyao Chen ◽  
Yong Lu ◽  
Alys M. Cheatle Jarvela ◽  
Leslie Pick
Keyword(s):  
Oncopeltus Fasciatus ◽  
Milkweed Bug ◽  
Pair Rule Gene ◽  
And Function ◽  
Gene Orthologs ◽  
Segmental Expression ◽  
Pair Rule

scholarly journals Segmental expression of Hoxb-1 is controlled by a highly conserved autoregulatory loop dependent upon exd/pbx

Cell ◽  
1995 ◽  
Vol 81 (7) ◽  
pp. 1031-1042 ◽  
Author(s):  
Helke Pöpperl ◽  
Mariann Bienz ◽  
Michèle Studer ◽  
Siu-Kwong Chan ◽  
Sam Aparicio ◽  
...  
Keyword(s):  
Segmental Expression

Segmental expression of Hox-2 homoeobox-containing genes in the developing mouse hindbrain

Nature ◽  
1989 ◽  
Vol 341 (6241) ◽  
pp. 405-409 ◽  
Author(s):  
David G. Wilkinson ◽  
Sangita Bhatt ◽  
Martyn Cook ◽  
Edorado Boncinelli ◽  
Robb Krumlauf
Keyword(s):  
Segmental Expression

Segmental expression of claudin proteins correlates with tight junction barrier properties in rat intestine

2010 ◽  
Vol 180 (4) ◽  
pp. 591-598 ◽  
Author(s):  
Alexander G. Markov ◽  
Anna Veshnyakova ◽  
Michael Fromm ◽  
Maren Amasheh ◽  
Salah Amasheh
Keyword(s):  
Tight Junction ◽  
Barrier Properties ◽  
Rat Intestine ◽  
Segmental Expression
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