Homeobox Genes in the CnidarianEleutheria dichotoma:Evolutionary Implications for the Origin ofAntennapedia-Class (HOM/Hox) Genes

Kuhn, Kerstin; Streit, Bruno; Schierwater, Bernd

doi:10.1006/mpev.1996.0055

Cited by 60 publications

(49 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, the cnox-5 gene, isolated so far only from Hydra (18), appeared as the diploblastic Mox counterpart. In contrast, the cnox-3 sequences, which were isolated from scyphozoan (28) and hydrozoan (18,23) species and as multiple copies in two species (23,28), are more heterogeneous than other cnox families. In all analyses, they form three groups that may come together depending on the type of analyses and selection of sequences (Figs.…”

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 92%

“…vicinity of anterior (PG-1͞2, Gsx) and posterior (PG-9͞10, cdx) Hox͞paraHox sequences from bilaterian species. The cnox-1 sequences isolated from anthozoan (17,31) and hydrozoan (15,18,22,23) species appeared as a monophyletic family in both NJ and ML trees (Figs. 2 and 3).…”

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

“…2). The cnox-2 HDs, present in anthozoan (D. Miller, personal communication), scyphozoan (28), hydrozoan (15,18,19,23,29), and placozoan (26) species, share 8 specific residues with the Gsx HDs. Moreover, in both the NJ and ML analyses, cnox-2 branches together clearly with the paraHox Gsx sequences.…”

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

“…Within the last years, a large number of diploblastic Antp-related genes have been isolated (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Among those, cnidarian sequences related to Hox and paraHox genes were found (15, 17-19, 22, 23, 25, 28, 29, 31), but the characterization of diploblastic Hox families, as well as their possible relatedness to triploblastic families, remains unclear in several cases (26,32).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Gauchat

Mazet

Berney

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

176

125

View full text Add to dashboard Cite

The conservation of developmental functions exerted by Antpclass homeoproteins in protostomes and deuterostomes suggested that homologs with related functions are present in diploblastic animals. Our phylogenetic analyses showed that Antp-class homeodomains belong either to non-Hox or to Hox͞paraHox families. Among the 13 non-Hox families, 9 have diploblastic homologs, Msx, Emx, Barx, Evx, Tlx, NK-2, and Prh͞Hex, Not, and Dlx, reported here. Among the Hox͞paraHox, poriferan sequences were not found, and the cnidarian sequences formed at least five distinct cnox families. Two are significantly related to the paraHox Gsx (cnox-2) and the mox (cnox-5) sequences, whereas three display some relatedness to the Hox paralog groups 1 (cnox-1), 9͞10 (cnox-3) and the paraHox cdx (cnox-4). Intermediate Hox͞paraHox genes (PG 3 to 8 and lox) did not have clear cnidarian counterparts. In Hydra, cnox-1, cnox-2, and cnox-3 were not found chromosomally linked within a 150-kb range and displayed specific expression patterns in the adult head. During regeneration, cnox-1 was expressed as an early gene whatever the polarity, whereas cnox-2 was up-regulated later during head but not foot regeneration. Finally, cnox-3 expression was reestablished in the adult head once it was fully formed. These results suggest that the Hydra genes related to anterior Hox͞paraHox genes are involved at different stages of apical differentiation. However, the positional information defining the oral͞aboral axis in Hydra cannot be correlated strictly to that characterizing the anterior-posterior axis in vertebrates or arthropods. T he discovery of structural and functional homologies between regulatory genes used by Drosophila and vertebrates during their development led to the hypothesis that animals would share a common set of genes for defining the head, trunk, and posterior regions at early developmental stages (1-6). The proposed genes were homeobox genes belonging either to the Antp class, like empty-spiracle (emx), even-skipped (evx), Hox genes, or to the Prd class, like orthodenticle (Otx), goosecoid. Phylogenetic analyses performed on a vast amount of Hox homeodomain (HD) sequences, including representatives from all classes of homeobox genes from animals, protozoa, fungi, and plants, confirmed the monophyly of the Antp class as well as its position as a sister group to the Paired class (7). Within the Antp class, the Hox gene organization is distinctive and enigmatic: the genes map in clusters, and the order of individual genes within a cluster correlates with their temporospatial expression pattern along the anterior-posterior body axis during development (8). Recently, it was proposed that the common bilaterian ancestor of protostomes and deuterostomes had at least seven Hox genes (9). However, the question of the composition of the ancestral HOX cluster remains open. Analysis of Hox homeobox sequences (10) suggested that the conserved HOX cluster emerged early in the evolution of metazoans from an original cluster harboring three ancestral g...

show abstract

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 92%

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

Section: High Conservation Of Non-hox Antp-class Gene Families In Metmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Gauchat

Mazet

Berney

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

176

125

View full text Add to dashboard Cite

show abstract

“…Three lines of evidence suggest that the interaction arose after divergence from angiosperms and, possibly, the origin of metazoa. First, the conserved hexapeptide is absent in the Abd-B class (32), which is phylogenetically distinct from other Antp genes (24), so only a subset of ANTP proteins show the interaction. Second, the hexapeptide is absent in the early metazoan group Cnidaria (32), so not all metazoan ANTP proteins show this interaction.…”

Section: Fig 1 (A)mentioning

confidence: 99%

Did homeodomain proteins duplicate before the origin of angiosperms, fungi, and metazoa?

Geeta

Janssen

Kellogg

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Homeodomain proteins are transcription factors that play a critical role in early development in eukaryotes. These proteins previously have been classified into numerous subgroups whose phylogenetic relationships are unclear. Our phylogenetic analysis of representative eukaryotic sequences suggests that there are two major groups of homeodomain proteins, each containing sequences from angiosperms, metazoa, and fungi. This result, based on parsimony and neighbor-joining analyses of primary amino acid sequences, was supported by two additional features of the proteins. The two protein groups are distinguished by an insertion͞deletion in the homeodomain, between helices I and II. In addition, an amphipathic alpha-helical secondary structure in the region N terminal of the homeodomain is shared by angiosperm and metazoan sequences in one group. These results support the hypothesis that there was at least one duplication of homeobox genes before the origin of angiosperms, fungi, and metazoa. This duplication, in turn, suggests that these proteins had diverse functions early in the evolution of eukaryotes. The shared secondary structure in angiosperm and metazoan sequences points to an ancient conserved functional domain.Homeodomain proteins originally were defined as gene products from the family of homeotic genes critical in development of Drosophila (1, 2). The term since has been applied to transcription factors that meet two criteria: four highly conserved residues including the absolutely conserved Trp-49 and a conserved secondary structure consisting of a helix-loophelix-turn-helix motif (3-5). Approximately 1,850 homeodomain proteins currently meet these criteria and occur in angiosperms, fungi, and metazoa. Understanding the evolutionary relationships of these transcription factors is of tremendous interest, because they play a vital role in a wide range of biological phenomena, including mating-type recognition, pathogenesis response, and early morphological development.Parsimony and neighbor-joining analyses of primary amino acid sequences of representative eukaryotic homeodomain proteins suggested a close relationship between certain angiosperm [e.g., knotted-like homeobox (KNOX)], metazoan [e.g., extradenticle (EXD)], and fungal [e.g., Cu homeostasis (CUP 9)] sequences. This result was further supported by two shared characters: an insertion͞deletion in the homeodomain, and an alpha-helical structure in the region N terminal of the homeodomain in the angiosperm and metazoan proteins. These characters differentiate this group of homeodomain proteins from metazoan antennapedia-like (ANTP) and other angiosperm, fungal, and metazoan sequences. This observation leads to the hypothesis that, in addition to recent duplications within each kingdom, there was at least one ancient duplication of homeodomain-encoding genes before the origin of angiosperms, fungi, and metazoa. The secondary structure shared by some angiosperm and metazoan proteins suggests an ancient shared function. On the other hand, the ph...

show abstract

Isolation of Hox genes from the scyphozoanCassiopeia xamachana: Implications for the early evolution of Hox genes

1999

View full text Add to dashboard Cite

Homeobox Genes in the CnidarianEleutheria dichotoma:Evolutionary Implications for the Origin ofAntennapedia-Class (HOM/Hox) Genes

Cited by 60 publications

References 10 publications

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Evolution of Antp-class genes and differential expression ofHydra Hox/paraHoxgenes in anterior patterning

Did homeodomain proteins duplicate before the origin of angiosperms, fungi, and metazoa?

Isolation of Hox genes from the scyphozoanCassiopeia xamachana: Implications for the early evolution of Hox genes

Contact Info

Product

Resources

About