Ectopic expression of the maize kn1 gene phenocopies the Hooded mutant of barley

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3737-3745 ◽  
Author(s):  
R.E. Williams-Carrier ◽  
Y.S. Lie ◽  
S. Hake ◽  
P.G. Lemaux
Keyword(s):  
Expression Pattern ◽  
Posttranscriptional Regulation ◽  
Cellular Differentiation ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Mrna Localization ◽  
Constitutive Promoter ◽  
Homeotic Transformation ◽  
Shoot Meristems

The homeobox gene, knotted1, (kn1) is expressed in shoot meristems and is required for maintaining indeterminacy and preventing cellular differentiation. Awns, extensions of the bract-like lemma found in all grass inflorescences, are normally determinate structures. We show that ectopic expression of kn1 in the barley awn is sufficient to direct the development of ectopic meristems, forming inflorescence-like structures. This homeotic transformation is similar to the phenotype produced by misexpression of the barley hvknox3 gene, associated with the dominant Hooded mutant (Muller, K. J., Romano, N., Gerstner, O., Garcia-Maroto, F., Pozzi, C., Salamini, F. and Rohde, W. (1995) Nature 374, 727–730). We suggest that the inverse polarity of the ectopic flowers seen in Hooded and transgenic kn1 plants results from the transformation of the awn into reiterative inflorescence axes. We observed that the protein and mRNA localization of the transgene, driven by a constitutive promoter, is similar to the expression pattern of hvknox3 in awns of Hooded mutants, suggesting posttranscriptional regulation.

Isolation and characterization of a downstream target of Pax6 in the mammalian retinal primordium

Development ◽  
2001 ◽  
Vol 128 (20) ◽  
pp. 3987-3994 ◽  
Author(s):  
Gilbert Bernier ◽  
Wolfgang Vukovich ◽  
Lorenz Neidhardt ◽  
Bernhard G. Herrmann ◽  
Peter Gruss
Keyword(s):  
Transcription Factor ◽  
Expression Pattern ◽  
Large Scale ◽  
Ectopic Expression ◽  
Signal Transduction Pathway ◽  
Homeobox Gene ◽  
Optic Vesicle ◽  
Altered Expression ◽  
Retina Development ◽  
Isolation And Characterization

The transcription factor Pax6 is required for eye morphogenesis in humans, mice and insects, and can induce ectopic eye formation in vertebrate and invertebrate organisms. Although the role of Pax6 has intensively been studied, only a limited number of genes have been identified that depend on Pax6 activity for their expression in the mammalian visual system. Using a large-scale in situ hybridization screen approach, we have identified a novel gene expressed in the mouse optic vesicle. This gene, Necab, encodes a putative cytoplasmic Ca2+-binding protein and coincides with Pax6 expression pattern in the neural ectoderm of the optic vesicle and in the forebrain pretectum. Remarkably, Necab expression is absent in both structures in Pax6 mutant embryos. By contrast, the optic vesicle-expressed homeobox genes Rx, Six3, Otx2 and Lhx2 do not exhibit an altered expression pattern. Using gain-of-function experiments, we show that Pax6 can induce ectopic expression of Necab, suggesting that Necab is a direct or indirect transcriptional target of Pax6. In addition, we have found that Necab misexpression can induce ectopic expression of the homeobox gene Chx10, a transcription factor implicated in retina development. Taken together, our results provide evidence that Necab is genetically downstream of Pax6 and that it is a part of a signal transduction pathway in retina development.

Homeotic transformation of the occipital bones of the skull by ectopic expression of a homeobox gene

Nature ◽  
1992 ◽  
Vol 359 (6398) ◽  
pp. 835-841 ◽  
Author(s):  
Thomas Lufkin ◽  
Manuel Mark ◽  
Charles P. Hart ◽  
Pascal Dollé ◽  
Marianne LeMeur ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Homeobox Gene ◽  
Homeotic Transformation

Homeobox genes in the functioning of plant meristems

1995 ◽  
Vol 350 (1331) ◽  
pp. 45-51 ◽  
Keyword(s):  
Molecular Markers ◽  
Gene Family ◽  
Leaf Morphology ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Positional Information ◽  
Specific Expression ◽  
Tobacco Leaf ◽  
Floral Meristems ◽  
Shoot Meristems

The maize homeobox gene knotted1 ( kn1 ) is expressed in vegetative and floral meristems and is down-regulated at the site of primordia formation. kn1 -related genes from maize and other species also show meristem-specific expression and offer additional tools for studying the activities of shoot meristems. Members of this gene family are expressed early in embryogenesis, providing molecular markers for meristem initiation. Ectopic expression of either kn1 or a related Arabidopsis gene, KNAT1 , causes dramatic alterations in Arabidopsis and tobacco leaf morphology. Most significantly, meristems form on the leaf, producing small shoots. We discuss whether the phenotypes can be interpreted as changes in positional information or timing of determination.

scholarly journals Analysis of maxillopedia Expression Pattern and Larval Cuticular Phenotype in Wild-Type and Mutant Tribolium

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 721-731 ◽  
Author(s):  
Teresa D Shippy ◽  
Jianhua Guo ◽  
Susan J Brown ◽  
Richard W Beeman ◽  
Robin E Denell
Keyword(s):  
Rna Interference ◽  
Expression Pattern ◽  
Tribolium Castaneum ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Homeotic Gene ◽  
Wild Type ◽  
Double Stranded Rna ◽  
Similar Expression ◽  
Mutant Phenotypes

Abstract The Tribolium castaneum homeotic gene maxillopedia (mxp) is the ortholog of Drosophila proboscipedia (pb). Here we describe and classify available mxp alleles. Larvae lacking all mxp function die soon after hatching, exhibiting strong transformations of maxillary and labial palps to legs. Hypomorphic mxp alleles produce less severe transformations to leg. RNA interference with maxillopedia double-stranded RNA results in phenocopies of mxp mutant phenotypes ranging from partial to complete transformations. A number of gain-of-function (GOF) mxp alleles have been isolated based on transformations of adult antennae and/or legs toward palps. Finally, we have characterized the mxp expression pattern in wild-type and mutant embryos. In normal embryos, mxp is expressed in the maxillary and labial segments, whereas ectopic expression is observed in some GOF variants. Although mxp and Pb display very similar expression patterns, pb null embryos develop normally. The mxp mutant larval phenotype in Tribolium is consistent with the hypothesis that an ancestral pb-like gene had an embryonic function that was lost in the lineage leading to Drosophila.

scholarly journals Complexity of Developmental Control: Analysis of Embryonic Cell Lineage Specification in Caenorhabditis elegans Using pes-1 as an Early Marker

Genetics ◽  
1999 ◽  
Vol 151 (1) ◽  
pp. 131-141
Author(s):  
Laurent Molin ◽  
Heinke Schnabel ◽  
Titus Kaletta ◽  
Richard Feichtinger ◽  
Ian A Hope ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Expression Pattern ◽  
Fusion Gene ◽  
Ectopic Expression ◽  
Gene Expression Pattern ◽  
Embryonic Cell ◽  
Control Analysis ◽  
Normal Pattern ◽  
Variable Expression ◽  
Founder Cells

Abstract In the early Caenorhabditis elegans embryo five somatic founder cells are born during the first cleavages. The first of these founder cells, named AB, gives rise to 389 of the 558 nuclei present in the hatching larva. Very few genes directly involved in the specification of the AB lineage have been identified so far. Here we describe a screen of a large collection of maternal-effect embryonic lethal mutations for their effect on the early expression of a pes-1::lacZ fusion gene. This fusion gene is expressed in a characteristic pattern in 14 of the 32 AB descendants present shortly after the initiation of gastrulation. Of the 37 mutations in 36 genes suspected to be required specifically during development, 12 alter the expression of the pes-1::lacZ marker construct. The gene expression pattern alterations are of four types: reduction of expression, variable expression, ectopic expression in addition to the normal pattern, and reduction of the normal pattern together with ectopic expression. We estimate that ∼100 maternal functions are required to establish the pes-1 expression pattern in the early embryo.

scholarly journals A Distinct Expression Pattern of the Long 3′-Untranslated Region Dicer mRNA and Its Implications for Posttranscriptional Regulation in Colorectal Cancer

2012 ◽  
Vol 3 (7) ◽  
pp. e17 ◽  
Author(s):  
Yasushi Hamaya ◽  
Shigeru Kuriyama ◽  
Tetsunari Takai ◽  
Ken-ichi Yoshida ◽  
Takanori Yamada ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Expression Pattern ◽  
Posttranscriptional Regulation ◽  
Untranslated Region

Requirements of Lim1, a Drosophila LIM-homeobox gene, for normal leg and antennal development

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4315-4323 ◽  
Author(s):  
T. Tsuji ◽  
A. Sato ◽  
I. Hiratani ◽  
M. Taira ◽  
K. Saigo ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Homeodomain Protein ◽  
Border Cells ◽  
Null Mutant ◽  
Tarsal Segment ◽  
Segment Boundary ◽  
Leg Development ◽  
Antagonistic Interactions

During Drosophila leg development, the distal-most compartment (pretarsus) and its immediate neighbour (tarsal segment 5) are specified by a pretarsus-specific homeobox gene, aristaless, and tarsal-segment-specific Bar homeobox genes, respectively; the pretarsus/tarsal-segment boundary is formed by antagonistic interactions between Bar and pretarsus-specific genes that include aristaless (Kojima, T., Sato, M. and Saigo, K. (2000) Development 127, 769–778). Here, we show that Drosophila Lim1, a homologue of vertebrate Lim1 encoding a LIM-homeodomain protein, is involved in pretarsus specification and boundary formation through its activation of aristaless. Ectopic expression of Lim1 caused aristaless misexpression, while aristaless expression was significantly reduced in Lim1-null mutant clones. Pretarsus Lim1 expression was negatively regulated by Bar and abolished in leg discs lacking aristaless activity, which was associated with strong Bar misexpression in the presumptive pretarsus. No Lim1 misexpression occurred upon aristaless misexpression. The concerted function of Lim1 and aristaless was required to maintain Fasciclin 2 expression in border cells and form a smooth pretarsus/tarsal-segment boundary. Lim1 was also required for femur, coxa and antennal development.

scholarly journals Author response: Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

2015 ◽  
Author(s):  
Benoît Landrein ◽  
Annamaria Kiss ◽  
Massimiliano Sassi ◽  
Aurélie Chauvet ◽  
Pradeep Das ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Homeobox Gene ◽  
Author Response ◽  
Shoot Meristems

A role for the vegetally expressed Xenopus gene Mix.1 in endoderm formation and in the restriction of mesoderm to the marginal zone

Development ◽  
1998 ◽  
Vol 125 (13) ◽  
pp. 2371-2380 ◽  
Author(s):  
P. Lemaire ◽  
S. Darras ◽  
D. Caillol ◽  
L. Kodjabachian
Keyword(s):  
Marginal Zone ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Early Response ◽  
Endoderm Differentiation ◽  
Head Formation ◽  
Mutual Repression ◽  
Regulatory Loop ◽  
Strong Activator

We have studied the role of the activin immediate-early response gene Mix.1 in mesoderm and endoderm formation. In early gastrulae, Mix.1 is expressed throughout the vegetal hemisphere, including marginal-zone cells expressing the trunk mesodermal marker Xbra. During gastrulation, the expression domains of Xbra and Mix.1 become progressively exclusive as a result of the establishment of a negative regulatory loop between these two genes. This mutual repression is important for the specification of the embryonic body plan as ectopic expression of Mix.1 in the Xbra domain suppresses mesoderm differentiation. The same effect was obtained by overexpressing VP16Mix.1, a fusion protein comprising the strong activator domain of viral VP16 and the homeodomain of Mix.1, suggesting that Mix.1 acts as a transcriptional activator. Mix.1 also has a role in endoderm formation. It cooperates with the dorsal vegetal homeobox gene Siamois to activate the endodermal markers edd, Xlhbox8 and cerberus in animal caps. Conversely, vegetal overexpression of enRMix.1, an antimorphic Mix.1 mutant, leads to a loss of endoderm differentiation. Finally, by targeting enRMix.1 expression to the anterior endoderm, we could test the role of this tissue during embryogenesis and show that it is required for head formation.

Msx1 antagonizes the myogenic activity of Pax3 in migrating limb muscle precursors

Development ◽  
1999 ◽  
Vol 126 (22) ◽  
pp. 4965-4976 ◽  
Author(s):  
A.J. Bendall ◽  
J. Ding ◽  
G. Hu ◽  
M.M. Shen ◽  
C. Abate-Shen
Keyword(s):  
Protein Interactions ◽  
Myogenic Differentiation ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Regulatory Elements ◽  
Limb Muscle ◽  
Chicken Embryos ◽  
Myogenic Activity ◽  
Myod Expression

The migration of myogenic precursors to the vertebrate limb exemplifies a common problem in development - namely, how migratory cells that are committed to a specific lineage postpone terminal differentiation until they reach their destination. Here we show that in chicken embryos, expression of the Msx1 homeobox gene overlaps with Pax3 in migrating limb muscle precursors, which are committed myoblasts that do not express myogenic differentiation genes such as MyoD. We find that ectopic expression of Msx1 in the forelimb and somites of chicken embryos inhibits MyoD expression as well as muscle differentiation. Conversely, ectopic expression of Pax3 activates MyoD expression, while co-ectopic expression of Msx1 and Pax3 neutralizes their effects on MyoD. Moreover, we find that Msx1 represses and Pax3 activates MyoD regulatory elements in cell culture, while in combination, Msx1 and Pax3 oppose each other's trancriptional actions on MyoD. Finally, we show that the Msx1 protein interacts with Pax3 in vitro, thereby inhibiting DNA binding by Pax3. Thus, we propose that Msx1 antagonizes the myogenic activity of Pax3 in migrating limb muscle precursors via direct protein-protein interaction. Our results implicate functional antagonism through competitive protein-protein interactions as a mechanism for regulating the differentiation state of migrating cells.

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