Background: The iroquois (iro/Irx) genes encode transcriptional regulators that belong to the TALE superclass of homeodomain proteins and have key functions during development in both vertebrates and insects. The Irx genes occur in one or two genomic clusters containing three genes each within the Drosophila and several vertebrate genomes, respectively. The similar genomic organization in Drosophila and vertebrates is widely considered as a result of convergent evolution, due to independent tandem gene duplications. In this study, we investigate the evolutionary history of the Irx genes at the scale of the whole metazoan kingdom.
Results: We identified in silico the putative full complement of Irx genes in the sequenced genomes of 36 different species representative of the main metazoan lineages, including non bilaterian species, several arthropods, non vertebrate chordates, and a basal vertebrate, the sea lamprey. We performed extensive phylogenetic analyses of the identified Irx genes and defined their genomic organizations. We found that, in most species, there are several Irx genes, these genes form two to four gene clusters, and the Irx genes are physically linked to a structurally and functionally unrelated gene known as CG10632 in Drosophila.
Conclusion: Three main conclusions can be drawn from our study. First, an Irx cluster composed of two genes, araucan/caupolican and mirror, is ancestral to the crustaceans+insects clade and has been strongly conserved in this clade. Second, three Irx genes were probably present in the last common ancestor of vertebrates and the duplication that has given rise to the six genes organized into two clusters found in most vertebrates, likely occurred in the gnathostome lineage after its separation from sea lampreys. Third, the clustered organization of the Irx genes in various evolutionary lineages may represent an exceptional case of convergent evolution or may point to the existence of an Irx gene cluster ancestral to bilaterians.
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http://dx.doi.org/10.1186/1471-2148-9-74 | DOI Listing |
PLoS One
December 2024
Dept. of Human and Animal Cell Lines, Leibniz-Institute DSMZ, Braunschweig, Germany.
Homeobox genes encode transcription factors which organize differentiation processes in all tissue types including the hematopoietic compartment. Recently, we have reported physiological expression of TALE-class homeobox gene IRX1 in early myelopoiesis restricted to the megakaryocyte-erythroid-progenitor stage and in early B-cell development to the pro-B-cell stage. In contrast, sister homeobox genes IRX2, IRX3 and IRX5 are aberrantly activated in the corresponding malignancies acute myeloid leukemia (AML) and B-cell progenitor acute lymphoid leukemia.
View Article and Find Full Text PDFCurr Med Chem
September 2024
Department of Respiratory and Critical Care Medicine, Emergency General Hospital, Beijing, 100028, China.
Background: The potential role of the iroquois homeobox (IRX) genes in tumorigenesis is a subject of interest, yet their specific involvement in lung adenocarcinoma (LUAD) has not been extensively examined.
Objective: This research endeavored to explore the impact of the IRX genes on the onset and progression of LUAD.
Methods: Utilizing data from The Cancer Genome Atlas (TCGA), samples of LUAD were selected for analysis.
Front Plant Sci
June 2024
Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology, Umeå, Sweden.
Drought is a major factor affecting crops, thus efforts are needed to increase plant resilience to this abiotic stress. The overlapping signaling pathways between drought and cell wall integrity maintenance responses create a possibility of increasing drought resistance by modifying cell walls. Here, using herbaceous and woody plant model species, and hybrid aspen, respectively, we investigated how the integrity of xylan in secondary walls affects the responses of plants to drought stress.
View Article and Find Full Text PDFOncologist
October 2024
Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, Brazil.
bioRxiv
May 2024
Department of Neurobiology, University of Chicago, Chicago, IL, USA.
The homeobox genes encode transcription factors with fundamental roles in animal development. Despite their link to various congenital conditions in humans, our understanding of gene expression, function, and regulation remains incomplete. Here, we conducted a systematic expression analysis of all six mouse genes in the embryonic spinal cord.
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