Segmental relationship between somites and vertebral column in zebrafish

Development ◽  
2002 ◽  
Vol 129 (16) ◽  
pp. 3851-3860 ◽  
Author(s):  
Elizabeth M. Morin-Kensicki ◽  
Ellie Melancon ◽  
Judith S. Eisen
Keyword(s):  
Vertebral Column ◽  
Hox Genes ◽  
De Novo ◽  
Expression Patterns ◽  
Axial Skeleton ◽  
Anteroposterior Axis ◽  
Tissue Interactions ◽  
Positional Identity ◽  
Regional Specificity

The segmental heritage of all vertebrates is evident in the character of the vertebral column. And yet, the extent to which direct translation of pattern from the somitic mesoderm and de novo cell and tissue interactions pattern the vertebral column remains a fundamental, unresolved issue. The elements of vertebral column pattern under debate include both segmental pattern and anteroposterior regional specificity. Understanding how vertebral segmentation and anteroposterior positional identity are patterned requires understanding vertebral column cellular and developmental biology. In this study, we characterized alignment of somites and vertebrae, distribution of individual sclerotome progeny along the anteroposterior axis and development of the axial skeleton in zebrafish. Our clonal analysis of zebrafish sclerotome shows that anterior and posterior somite domains are not lineage-restricted compartments with respect to distribution along the anteroposterior axis but support a ‘leaky’ resegmentation in development from somite to vertebral column. Alignment of somites with vertebrae suggests that the first two somites do not contribute to the vertebral column. Characterization of vertebral column development allowed examination of the relationship between vertebral formula and expression patterns of zebrafish Hox genes. Our results support co-localization of the anterior expression boundaries of zebrafish hoxc6 homologs with a cervical/thoracic transition and also suggest Hox-independent patterning of regionally specific posterior vertebrae.

Genetic interactions and dosage effects of Polycomb group genes in mice

Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3543-3551 ◽  
Author(s):  
S. Bel ◽  
N. Core ◽  
M. Djabali ◽  
K. Kieboom ◽  
N. Van der Lugt ◽  
...  
Keyword(s):  
Hox Genes ◽  
Expression Patterns ◽  
Axial Skeleton ◽  
Polycomb Group ◽  
Genetic Interactions ◽  
Homeotic Gene ◽  
Polycomb Group Genes ◽  
Dosage Effects ◽  
Somitic Mesoderm ◽  
Homeotic Gene Expression

In Drosophila and mouse, Polycomb group genes are involved in the maintenance of homeotic gene expression patterns throughout development. Here we report the skeletal phenotypes of compound mutants for two Polycomb group genes bmi1 and M33. We show that mice deficient for both bmi1 and M33 present stronger homeotic transformations of the axial skeleton as compared to each single Polycomb group mutant, indicating strong dosage interactions between those two genes. These skeletal transformations are accompanied with an enhanced shift of the anterior limit of expression of several Hox genes in the somitic mesoderm. Our results demonstrate that in mice the Polycomb group genes act in synergy to control the nested expression pattern of some Hox genes in somitic mesodermal tissues during development.

scholarly journals De novo Characterization of the Platycladus orientalis Transcriptome and Analysis of Photosynthesis-Related Genes during Aging

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 393
Author(s):  
Ermei Chang ◽  
Jin Zhang ◽  
Xiamei Yao ◽  
Shuo Tang ◽  
Xiulian Zhao ◽  
...  
Keyword(s):  
De Novo ◽  
Average Length ◽  
Transcriptome Assembly ◽  
Expression Patterns ◽  
Age And Growth ◽  
Potential Candidate ◽  
Platycladus Orientalis ◽  
Oxidation Reduction ◽  
Old Trees

In China, Platycladus orientalis has a lifespan of thousands of years. The long lifespan of these trees may be relevant for the characterization of plant aging at the molecular level. However, the molecular mechanism of the aging process of P. orientalis is still unknown. To explore the relationship between age and growth of P. orientalis, we analyzed physiological changes during P. orientalis senescence. The malondialdehyde content was greater in 200-, 700-, and 1100-year-old ancient trees than in 20-year-old trees, whereas the peroxidase and superoxide dismutase activities, as well as the soluble protein content, exhibited the opposite trend. Furthermore, we performed a de novo transcriptome assembly using RNA-Seq and obtained 48,044 unigenes with an average length of 896 bp. A total of 418 differentially expressed genes were identified in different stages of aging of P. orientalis. Clustering analysis revealed distinct timepoints at which the oxidation–reduction and photosynthesis pathways changed. Eight clusters with distinct expression patterns were identified. The expression levels of photosynthesis-, oxidation–reduction-, and transporter-related genes were down-regulated, whereas those of transcription-, signaling-, and senescence-related genes were up-regulated during aging. In addition, consistent with the most obviously down-regulated genes of photosynthesis-related genes, the photosynthetic indexes including chlorophyll a and b levels decreased steadily during P. orientalis aging. This study combined transcriptome with physiological and biochemical data, revealing potential candidate genes influencing senescence during P. orientalis aging.

scholarly journals Making Headway: The Roles of Hox Genes and Neural Crest Cells in Craniofacial Development

2003 ◽  
Vol 3 ◽  
pp. 240-264 ◽  
Author(s):  
Paul A. Trainor
Keyword(s):  
Neural Crest ◽  
Hox Genes ◽  
Neural Crest Cell ◽  
Axial Skeleton ◽  
Craniofacial Development ◽  
Congenital Defects ◽  
Connective Tissues ◽  
Surface Ectoderm ◽  
Head Development ◽  
Tissue Interactions

Craniofacial development is an extraordinarily complex process requiring the orchestrated integration of multiple specialized tissues such as the surface ectoderm, neural crest, mesoderm, and pharyngeal endoderm in order to generate the central and peripheral nervous systems, axial skeleton, musculature, and connective tissues of the head and face. How do the characteristic facial structures develop in the appropriate locations with their correct shapes and sizes, given the widely divergent patterns of cell movements that occur during head development? The patterning information could depend upon localized interactions between the epithelial and mesenchymal tissues or alternatively, the developmental program for the characteristic facial structures could be intrinsic to each individual tissue precursor. Understanding the mechanisms that control vertebrate head development is an important issue since craniofacial anomalies constitute nearly one third of all human congenital defects. This review discusses recent advances in our understanding of neural crest cell patterning and the dynamic nature of the tissue interactions that are required for normal craniofacial development.

Comparative osteology of the axial skeleton of the genus Pampus (Family: Stromateidae, Perciformes)

2016 ◽  
Vol 97 (2) ◽  
pp. 277-287 ◽  
Author(s):  
Laith A. Jawad ◽  
Liu Jig
Keyword(s):  
Vertebral Column ◽  
Axial Skeleton ◽  
Caudal Fin ◽  
Fin Rays ◽  
Osteological Characters ◽  
Comparative Osteology

Seven osteological characters of the axial skeleton are studied in the eight species of the genus Pampus. The characters include: pattern of interdigitation of the dorsal- and anal-fin pterygiophores with the neural and haemal spines of the vertebrae, structure of the vertebral column, distribution of the dorsal- and ventral- procurrent caudal-fin rays, distribution of the principal caudal-fin rays and the morphology of the caudal-fin skeleton. All these features appear to be useful in the characterization of the eight species of the genus Pampus. Formulae for the structure of the vertebral column, the dorsal- and anal-fin pterygiophores’ interdigitation with the neural and haemal spines of the vertebrae, distribution of the dorsal and ventral procurrent caudal-fin rays, and distribution of the principal caudal-fin rays were developed. Pampus nozawae was recently considered a synonym of P. argenteus. However, according to the characters used in the present study, this species is notably distinct from P. argenteus.

Functional cooperation between the non-paralogous genes Hoxa-10 and Hoxd-11 in the developing forelimb and axial skeleton

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 449-460 ◽  
Author(s):  
B. Favier ◽  
F.M. Rijli ◽  
C. Fromental-Ramain ◽  
V. Fraulob ◽  
P. Chambon ◽  
...  
Keyword(s):  
Hox Genes ◽  
Expression Patterns ◽  
Axial Skeleton ◽  
Proximal Region ◽  
Mutant Mice ◽  
Phenotypic Traits ◽  
Femoral Trochlea ◽  
Preferential Expression ◽  
Caudal Vertebrae ◽  
Compound Mutation

The Abdominal B-related Hoxa-10 gene displays similar expression patterns in the differentiating forelimbs and hindlimbs of the mouse, with preferential expression around the humeral and femoral cartilages and more diffuse expression in distal regions. We found that a targeted disruption of Hoxa-10 has almost no effect in the forelimbs, while it affects the proximal hindlimb skeleton. The alterations were located along the dorsolateral side of the femur (labium laterale), with an enlargement and distal shift of the third trochanter, a misshapen lateral knee sesamoid, a supernumerary ‘ligament’ connecting these structures and an occasional duplication of the femoral trochlea. Some Hoxa-10−/− mutant mice developed severe degenerative alterations of the knee articulation upon ageing. Viable Hoxa-10/Hoxd-11 double mutant mice were produced by genetic intercrosses. The compound mutation resulted in synergistic forelimb phenotypic alterations, consisting of: (i) an exacerbation of Hoxd-11−/− phenotypic traits in the carpal and digital region, e.g. more pronounced truncations of the ulna styloid, pyramidal and pisiform bones and of some metacarpal and phalangeal bones and (ii) marked alterations in a more proximal region which is nearly unaffected in Hoxd-11−/− single mutants; the entire radius and ulna were truncated and thickened, with deformations of the ulna proximal extremity. Thus, functional redundancy can occur even between non-paralogous Abdominal B-related Hox genes. The double Hoxa-10/Hoxd-11 mutation also conferred full penetrance to the sacral and caudal vertebrae transformations which are approximately 50% penetrant in Hoxd-11−/− single mutants, revealing that functional cooperation can also occur between non-paralogous Hox gene products in axial skeleton patterning.

Comprehensive HOX Gene Expression Profiles Are Associated with Major Cytogenetic Prognostic Categories in AML.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2989-2989
Author(s):  
Harry A. Drabkin ◽  
Vivian Ruvolo ◽  
Sharvari Gadgil ◽  
Wenjing Chen ◽  
Chan Zeng ◽  
...  
Keyword(s):  
Cell Fate ◽  
Hox Genes ◽  
De Novo ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Gene Expression Profiles ◽  
Model Systems ◽  
Acute Leukemias ◽  
Hox Gene ◽  
Cd34 Cells

Abstract The homeodomain genes comprise a set of transcription factors that determine cell fate by regulating proliferation, development, and apoptosis. Humans have 39 class I homeodomain genes (HOX) that occur in four clusters (HOXA, HOXB, HOXC, and HOXD). During development HOX expression takes place according to the position of a gene within its cluster and the position of the cell along the anterior - posterior axis. Some HOX genes are expressed in adult tissues, where they are thought to regulate the regenerative differentiation of cells. If one were to view leukemia as a disorder of regenerative hematopoesis, one could hypothesize that dysregulation of HOX expression promotes leukemogenesis. The role of some homeodomain genes in acute leukemia has been especially well studied. In mouse model systems, overexpression of HOXA7, HOXA9 and Meis1 lead to AML. Chromosomal translocations targeting HOX and other homeodomain genes are associated with acute myeloid and lymphoid leukemias. Previous results have suggested that HOX expression patterns might define certain AML subsets. In the present study, we analyzed the expression of 40 homeodomain genes, among them 25 of the HOXA-D genes, in leukemic enriched samples from 66 patients with de novo AML and in sorted CD34+ cells derived from four healthy bone marrow donors. Also, in order to integrate any effects of mutations in FLT3, C/EBPa, and nucleophosmin (NPM) on HOX expression, we assessed the presence of mutations in these three genes. Our results demonstrate that HOX expression patterns are intimately linked to particular cytogenetic abnormalities. The most striking overall findings were the overexpression of HOXA and HOXB genes in AMLs with NPM mutations, the similarity of HOX expression in AMLs with unfavorable cytogenetics to that of AMLs with intermediate cytogenetics, and the downregulation of HOXA genes in core binding factor (CBF) AMLs. Moreover, AMLs with translocations involving CBFbeta had distinctly higher expression of HOXB2, HOXB3, HOXB4, and Meis 1 than did patients with translocations involving CBFalpha. Some HOX genes displayed no heterogeneity of expression and are thus likely unrelated to leukemogenesis. Other genes, particularly HOXA and HOXB genes, displayed marked heterogeneity of expression and thus may have a role in leukemogenesis. However, every AML had substantial differences in the expression of at least one HOX gene compared to normal CD34+ cells. In addition, levels of HOX expression distinguished within individual cytogenetic groups certain subsets, including cases with inv(16) and cases that phenotypically resembled NPM mutations. Based on these results and the causative nature of HOX deregulation in some acute leukemias, we postulate that the HOX expression patterns exemplified here may be responsible for some (or many) of the biologic differences observed among the major cytogenetic prognostic groups.

scholarly journals Separate elements cause lineage restriction and specify boundaries of Hox-1.1 expression

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 279-287 ◽  
Author(s):  
A.W. Puschel ◽  
R. Balling ◽  
P. Gruss
Keyword(s):  
Transgenic Mice ◽  
Hox Genes ◽  
Positional Information ◽  
Regulatory Elements ◽  
Specific Region ◽  
Regulatory Sequences ◽  
Anteroposterior Axis ◽  
Positional Identity ◽  
Developmental Programme ◽  
Responsive Element

The Hox genes are a class of putative developmental control genes that are thought to be involved in the specification of positional identity along the anteroposterior axis of the vertebrate embryo. It is apparent from their expression pattern that their regulation is dependent upon positional information. In a previous analysis of the Hox-1.1 promoter in transgenic mice, we identified sequences that were sufficient to establish transgene expression in a specific region of the embryo. The construct used, however, did not contain enough regulatory sequences to reproduce all aspects of Hox-1.1 expression. In particular, neither a posterior boundary nor a restriction of expression to prevertebrae was achieved. Here we show correct regulation by Hox-1.1 sequences in transgenic mice and identify the elements responsible for different levels of control. Concomitant with the subdivision of mesodermal cells into different lineages during gastrulation and organogenesis, Hox-1.1 expression is restricted to successively smaller sets of cells. Distinct elements are required at different stages of development to execute this developmental programme. One position-responsive element (130 bp nontranslated leader) was shown to be crucial for the restriction of expression not only along the anteroposterior axis of the embryo, setting the posterior border, but also along the dorsoventral axis of the neural tube and to the lineage giving rise to the prevertebrae. Thus, Hox-1.1 expression is established in a specific region of the embryo and in a specific lineage of the mesoderm by restricting the activity of the promoter by the combined effect of several regulatory elements.

Loss- and gain-of-function mutations show a polycomb group function for Ring1A in mice

Development ◽  
2000 ◽  
Vol 127 (23) ◽  
pp. 5093-5100 ◽  
Author(s):  
M. del Mar Lorente ◽  
C. Marcos-Gutierrez ◽  
C. Perez ◽  
J. Schoorlemmer ◽  
A. Ramirez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hox Genes ◽  
Gene Dosage ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Axial Skeleton ◽  
Polycomb Group ◽  
Genetic Evidence ◽  
Molecular Evidence ◽  
Group Function

The products of the Polycomb group (PcG) of genes act as transcriptional repressors involved in the maintenance of homeotic gene expression patterns throughout development, from flies to mice. Biochemical and molecular evidence suggests that the mouse Ring1A gene is a member of the PcG of genes. However, genetic evidence is needed to establish PcG function for Ring1A, since contrary to all other murine PcG genes, there is no known Drosophila PcG gene encoding a homolog of the Ring1A protein. To study Ring1A function we have generated a mouse line lacking Ring1A and mouse lines overexpressing Ring1A. Both Ring1A(−/−)and Ring1A(+/−) mice show anterior transformations and other abnormalities of the axial skeleton, which indicates an unusual sensitivity of axial skeleton patterning to Ring1A gene dosage. Ectopic expression of Ring1A also results in dose-dependent anterior transformations of vertebral identity, many of which, interestingly, are shared by Ring1A(−/−) mice. In contrast, the alterations of Hox gene expression observed in both type of mutant mice are subtle and involve a reduced number of Hox genes. Taken together, these results provide genetic evidence for a PcG function of the mouse Ring1A gene.

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