Distal-less-related homeobox genes of vertebrates: Evolution, function, and regulation

2000 ◽  
Vol 78 (5) ◽  
pp. 593-601 ◽  
Author(s):  
Ted Zerucha ◽  
Marc Ekker
Keyword(s):  
Homeobox Genes ◽  
Gene Families ◽  
Duplication Event ◽  
Developmental Expression ◽  
Gene Clustering ◽  
Tandem Gene Duplication ◽  
Current State ◽  
Branchial Arches ◽  
Genomic Scale ◽  
Dlx Genes

Homeobox genes of the Distal-less family have been identified in virtually all metazoan groups where they play roles in the ontogeny of these animals. The vertebrate Distal-less related genes (Dlx genes) are thought to have arisen as a result of a tandem gene duplication event followed by a number of larger genomic scale duplications and thus represent an interesting model with which to study the evolution of clustered gene families. Dlx genes are involved in the development of the forebrain, branchial arches, sensory organs, and limbs. Here we describe the current state of knowledge of the Dlx genes in terms of their developmental expression, how this expression is regulated and how the products of these genes function, once expressed. We highlight a number of recent studies that have shed light on the transcriptional regulation of this gene family. These findings have not only contributed to our understanding of the selective pressures involved in the maintenance of familial gene clustering in genomes, but also to our understanding of how genes may diverge in function during the course of evolution as a result of divergence of regulatory mechanisms.Key words: genome, homeodomain, inner ear, olfactory placode, transcription.

scholarly journals Six mouse alpha-tubulin mRNAs encode five distinct isotypes: testis-specific expression of two sister genes.

1986 ◽  
Vol 6 (7) ◽  
pp. 2409-2419 ◽  
Author(s):  
A Villasante ◽  
D Wang ◽  
P Dobner ◽  
P Dolph ◽  
S A Lewis ◽  
...  
Keyword(s):  
Duplication Event ◽  
Developmental Expression ◽  
Untranslated Regions ◽  
Coding Region ◽  
Specific Expression ◽  
Translational Initiation ◽  
Alpha Tubulin ◽  
Tubulin Isotypes ◽  
Tubulin Isotype ◽  
Genes Encoding

Five mouse alpha-tubulin isotypes are described, each distinguished by the presence of unique amino acid substitutions within the coding region. Most, though not all of these isotype-specific amino acids, are clustered at the carboxy terminus. One of the alpha-tubulin isotypes described is expressed exclusively in testis and is encoded by two closely related genes (M alpha 3 and M alpha 7) which have homologous 3' untranslated regions but which differ at multiple third codon positions and in their 5' untranslated regions. We show that a subfamily of alpha-tubulin genes encoding the same testis-specific isotype also exists in humans. Thus, we conclude that the duplication event leading to a pair of genes encoding a testis-specific alpha-tubulin isotype predated the mammalian radiation, and both members of the duplicated sequence have been maintained since species divergence. A second alpha-tubulin gene, M alpha 6, is expressed ubiquitously at a low level, whereas a third gene, M alpha 4, is unique in that it does not encode a carboxy-terminal tyrosine residue. This gene yields two transcripts: a 1.8-kilobase (kb) mRNA that is abundant in muscle and a 2.4-kb mRNA that is abundant in testis. Whereas the 1.8-kb mRNA encodes a distinct alpha-tubulin isotype, the 2.4-kb mRNA is defective in that the methionine residue required for translational initiation is missing. Patterns of developmental expression of the various alpha-tubulin isotypes are presented. Our data support the view that individual tubulin isotypes are capable of conferring functional specificity on different kinds of microtubules.

Developmental expression of transforming growth factors alpha and beta in mouse fetus

1988 ◽  
Vol 8 (8) ◽  
pp. 3415-3422
Author(s):  
J N Wilcox ◽  
R Derynck
Keyword(s):  
Transforming Growth Factor ◽  
Developmental Expression ◽  
Otic Vesicle ◽  
Tgf Beta ◽  
Hematopoietic Organ ◽  
Mouse Fetus ◽  
Branchial Arches ◽  
Factor Alpha ◽  
And Function

Expression of mRNA for transforming growth factor alpha (TGF-alpha) and TGF-beta 1 during the fetal development of mice was evaluated by in situ hybridization. TGF-alpha mRNA was detected in 9- and 10-day fetuses but was absent in older fetuses. TGF-alpha mRNA-containing cells were found in the placenta, otic vesicle, oral cavity, pharyngeal pouch, first and second branchial arches, and developing kidneys. mRNA for TGF-beta 1 was present in hematopoietic cells of blood islands and capillaries and in the liver as it began to bud off on day 10 and function as a hematopoietic organ.

Developmental expression of the alpha receptor for platelet-derived growth factor, which is deleted in the embryonic lethal Patch mutation

Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 289-303 ◽  
Author(s):  
A. Orr-Urtreger ◽  
M.T. Bedford ◽  
M.S. Do ◽  
L. Eisenbach ◽  
P. Lonai
Keyword(s):  
Primitive Streak ◽  
Yolk Sac ◽  
Developmental Expression ◽  
Wild Type ◽  
Neural Tubes ◽  
Pdgfra Gene ◽  
Branchial Arches ◽  
Early Organogenesis ◽  
Visceral Yolk Sac ◽  
Parietal Endoderm

The alpha receptor of PDGF (Pdgfra) is expressed in primitive endoderm and mesoderm derivatives throughout embryogenesis. In the early primitive streak stage the gene is transcribed in the visceral and parietal endoderm. Later it is expressed in the presomitic mesoderm, yolk sac and amnion. During somitogenesis its transcription localizes to the heart and the somites. Subsequently, it is transcribed in the dermatome, the sclerotome, the developing limb and in various mesenchymal tissues of visceral organs. Its wild-type expression pattern correlates well with the phenotype of homozygous mutant Patch (Ph) embryos, where the Pdgfra gene is deleted. The Ph phenotype is first detectable at the primitive streak stage with convoluted and hypertrophic visceral yolk sac, deformed neural plate and disorganized or missing mesoderm. Most Ph/Ph embryos die before the 11th day of gestation. Those that survive till early organogenesis are very small, have hypertrophic yolk sacs, small and undifferentiated somites, convoluted neural tubes, large heart and pericardium, rudimentary limb buds and branchial arches. Our observations together suggest that the alpha PDGF receptor may be required for the normal development of visceral endoderm and mesoderm derivatives.

scholarly journals Promoter-mediated diversification of transcriptional bursting dynamics following gene duplication

2018 ◽  
Vol 115 (33) ◽  
pp. 8364-8369 ◽  
Author(s):  
Edward Tunnacliffe ◽  
Adam M. Corrigan ◽  
Jonathan R. Chubb
Keyword(s):  
Gene Duplication ◽  
Expression Profiles ◽  
Single Cells ◽  
Family Members ◽  
Gene Families ◽  
Developmental Expression ◽  
Upstream Sequence ◽  
Genomic Context ◽  
Entire Family ◽  
Transcriptional Bursting

During the evolution of gene families, functional diversification of proteins often follows gene duplication. However, many gene families expand while preserving protein sequence. Why do cells maintain multiple copies of the same gene? Here we have addressed this question for an actin family with 17 genes encoding an identical protein. The genes have divergent flanking regions and are scattered throughout the genome. Surprisingly, almost the entire family showed similar developmental expression profiles, with their expression also strongly coupled in single cells. Using live cell imaging, we show that differences in gene expression were apparent over shorter timescales, with family members displaying different transcriptional bursting dynamics. Strong “bursty” behaviors contrasted steady, more continuous activity, indicating different regulatory inputs to individual actin genes. To determine the sources of these different dynamic behaviors, we reciprocally exchanged the upstream regulatory regions of gene family members. This revealed that dynamic transcriptional behavior is directly instructed by upstream sequence, rather than features specific to genomic context. A residual minor contribution of genomic context modulates the gene OFF rate. Our data suggest promoter diversification following gene duplication could expand the range of stimuli that regulate the expression of essential genes. These observations contextualize the significance of transcriptional bursting.

Ancient and recent duplications of the rainbow trout Wilms' tumor gene

Genome ◽  
2001 ◽  
Vol 44 (3) ◽  
pp. 455-462 ◽  
Author(s):  
Joseph P Brunelli ◽  
Barrie D Robison ◽  
Gary H Thorgaard
Keyword(s):  
Rainbow Trout ◽  
Tumor Suppressor ◽  
Wilms Tumor ◽  
Gene Families ◽  
Duplication Event ◽  
Tissue Expression ◽  
Wt1 Gene ◽  
Rt Pcr ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Bony Fishes

The Wilms' tumor suppressor (WT1) gene plays an important role in the development and functioning of the genitourinary system, and mutations in this gene are associated with nephroblastoma formation in humans. Rainbow trout (Oncorhynchus mykiss) is one of the rare animal models that readily form nephroblastomas, yet trout express three distinct WT1 genes, one of which is duplicated and inherited tetrasomically. Sequence analyses suggest an ancient gene duplication in the common ancestor of bony fishes resulted in the formation of two WT1 gene families, that conserve the splicing variations of tetrapod WT1, and a second duplication event occurred in the trout lineage. The WT1 genes of one family map to linkage groups 6 and 27 in the trout genome map. Reverse transcribed polymerase chain reaction (RT-PCR) expression analysis demonstrated little difference in WT1 tissue expression pattern between genes.Key words: tumor suppressor, nephroblastoma, RT-PCR expression, kidney, cancer, cDNA, gene mapping.

scholarly journals Identification and Expression Profiling of the BTB Domain-Containing Protein Gene Family in the Silkworm,Bombyx mori

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Daojun Cheng ◽  
Wenliang Qian ◽  
Meng Meng ◽  
Yonghu Wang ◽  
Jian Peng ◽  
...  
Keyword(s):  
Protein Gene ◽  
Domain Architecture ◽  
Gene Families ◽  
Monarch Butterfly ◽  
Duplication Event ◽  
Orthologous Relationship ◽  
Specific Expression ◽  
Protein Protein Interaction ◽  
Btb Domain ◽  
Silkworm Bombyx Mori

The BTB domain is a conserved protein-protein interaction motif. In this study, we identified 56 BTB domain-containing protein genes in the silkworm, in addition to 46 in the honey bee, 55 in the red flour beetle, and 53 in the monarch butterfly. Silkworm BTB protein genes were classified into nine subfamilies according to their domain architecture, and most of them could be mapped on the different chromosomes. Phylogenetic analysis suggests that silkworm BTB protein genes may have undergone a duplication event in three subfamilies: BTB-BACK-Kelch, BTB-BACK-PHR, and BTB-FLYWCH. Comparative analysis demonstrated that the orthologs of each of 13 BTB protein genes present a rigorous orthologous relationship in the silkworm and other surveyed insects, indicating conserved functions of these genes during insect evolution. Furthermore, several silkworm BTB protein genes exhibited sex-specific expression in larval tissues or at different stages during metamorphosis. These findings not only contribute to a better understanding of the evolution of insect BTB protein gene families but also provide a basis for further investigation of the functions of BTB protein genes in the silkworm.

scholarly journals Duplication of chickendefensin7gene generated by gene conversion and homologous recombination

2016 ◽  
Vol 113 (48) ◽  
pp. 13815-13820 ◽  
Author(s):  
Mi Ok Lee ◽  
Susanne Bornelöv ◽  
Leif Andersson ◽  
Susan J. Lamont ◽  
Junfeng Chen ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Copy Number Variation ◽  
Gene Conversion ◽  
Copy Number ◽  
Computational Prediction ◽  
Gene Families ◽  
Duplication Event ◽  
Promoter Regions ◽  
Large Gene ◽  
Number Variation

Defensins constitute an evolutionary conserved family of cationic antimicrobial peptides that play a key role in host innate immune responses to infection. Defensin genes generally reside in complex genomic regions that are prone to structural variation, and defensin genes exhibit extensive copy number variation in humans and in other species. Copy number variation of defensin genes was examined in inbred lines of Leghorn and Fayoumi chickens, and a duplication ofdefensin7was discovered in the Fayoumi breed. Analysis of junction sequences confirmed the occurrence of a simple tandem duplication ofdefensin7with sequence identity at the junction, suggesting nonallelic homologous recombination betweendefensin7anddefensin6. The duplication event generated two chimeric promoters that are best explained by gene conversion followed by homologous recombination. Expression ofdefensin7was not elevated in animals with two genes despite both genes being transcribed in the tissues examined. Computational prediction of promoter regions revealed the presence of several putative transcription factor binding sites generated by the duplication event. These data provide insight into the evolution and possible function of large gene families and specifically, the defensins.

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