odd-skipped homologs function during gut development in C. elegans

Expression of the odd-2 Gene in C. elegans

The odd-2 gene in C. elegans is an orthologue of the odd-skipped gene in Drosophila and the odd-skipped related genes in mammals. The mammalian genes have been shown to be expressed in a variety of tissues and cancers. It was previously reported that ODD-2 is expressed in the intestine and shows some expression outside of the intestine in the tail region. Using a partial ODD-2 ::GFP fusion, we hypothesize that the expression outside of the intestine may be in rectal gland cells, and we also report that ODD-2 may be expressed in the germline sheath cells.

Alterations in ileal transcriptomics during an intestinal barrier challenge in lactating Holstein cows fed a Saccharomyces cerevisiae fermentation product identify potential regulatory processes

Stressors such as lack of access to feed, hot temperatures, transportation, and pen changes can cause impairment of ruminal and intestinal barrier function, also known as "leaky gut". Despite the known benefits of some nutritional approaches during periods of stress, little is understood regarding the underlying mechanisms, especially in dairy cows. We evaluated the effect of feeding a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) on the ileal transcriptome in response to feed restriction (FR), an established model to induce intestinal barrier dysfunction. Multiparous cows [97.1 ± 7.6 days in milk (DIM); n = 5/group] fed a control diet or control plus 19 g/d SCFP for 9 wk were subjected to an FR challenge for 5 d during which they were fed 40% of their ad libitum intake from the 7 d before FR. All cows were slaughtered at the end of FR, and ileal scrapping RNA was used for RNAseq (NovaSeq 6000, 100 bp read length). Statistical analysis was performed in R and bioinformatics using the KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO databases. One thousand six hundred and ninety-six differentially expressed genes (DEG; FDR-adjusted P ≤ 0.10) were detected in SCFP vs. control, with 451 upregulated and 1,245 downregulated. "Mucin type O-glycan biosynthesis" was the top downregulated KEGG pathway due to downregulation of genes catalyzing glycosylation of mucins (GCNT3, GALNT5, B3GNT3, GALNT18, and GALNT14). An overall downregulation of cell and tissue structure genes (e.g., extracellular matrix proteins) associated with collagen (COL6A1, COL1A1, COL4A1, COL1A2, and COL6A2), laminin (LAMB2), and integrins (ITGA8, ITGA2, and ITGA5) also were detected with SCFP. A subset of DEG enriched in the GO term "extracellular exosome" and "extracellular space". Chemokines within "Cytokine-cytokine receptor interaction pathways" such as CCL16, CCL21, CCL14, CXCL12, and CXCL14 were downregulated by SCFP. The "Glutathione metabolism" pathway was upregulated by SCFP, including GSTA1 and RRM2B among the top upregulated genes, and GSTM1 and GPX8 as top downregulated genes. There were 9 homeobox transcription factors among the top 50 predicted transcription factors using the RNAseq DEG dataset, underscoring the importance of cell differentiation as a potential target of dietary SCFP. Taken together, SCFP downregulated immune-, ECM-, and mucin synthesis-related genes during FR. Homeobox transcription factors appear important for the transcriptional response of SCFP.

Sob gene is critical to wing development in Bombyx mori and Tribolium castaneum

The development of insect appendages requires the expression of multiple genes in a strict spatial and temporal order. The odd-skipped family genes are vital transcriptional factors involved in embryonic development. The development and morphogenesis of the insect wing requires multiple transcription factors to regulate the expression of wing patterning genes at the transcriptional level. However, the function of odd-related genes in insect wing morphogenesis and development during postembryonic stages is unclear. We focused on the roles of the sister of odd and bowl (sob) gene, a member of odd-skipped family genes, during the wing morphopoiesis in Bombyx mori using the clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 system and in Tribolium castaneum by RNA interference. The results showed that the wings were significantly smaller and degenerated, and wing veins were indistinct in the sob gene loss-of-function group in both B. mori and T. castaneum. Quantitative real-time polymerase chain reaction revealed that the Tcsob gene regulated the expression of wing development genes, such as the cht 7 and the vg gene. The findings suggest the importance of sob gene in insect wing morphology formation during postembryonic stages.

The odd-1(tm848) mutation has no significant effect on brood size in Caenorhabditis elegans

The genome of Caenorhabditis elegans contains two genes of the odd-skipped transcription factor family, odd-1 and odd-2. In C. elegans, odd-1 is expressed in the intestine. A deletion mutant (tm848) that removes most of the odd-1 gene, including all three zinc fingers, has no significant effect on brood size when compared to wild-type worms.

A 4D single-cell protein atlas of transcription factors delineates spatiotemporal patterning during embryogenesis

Complex biological processes such as embryogenesis require precise coordination of cell differentiation programs across both space and time. Using protein-fusion fluorescent reporters and four-dimensional live imaging, we present a protein expression atlas of transcription factors (TFs) mapped onto developmental cell lineages during Caenorhabditis elegans embryogenesis, at single-cell resolution. This atlas reveals a spatiotemporal combinatorial code of TF expression, and a cascade of lineage-specific, tissue-specific and time-specific TFs that specify developmental states. The atlas uncovers regulators of embryogenesis, including an unexpected role of a skin specifier in neurogenesis and the critical function of an uncharacterized TF in convergent muscle differentiation. At the systems level, the atlas provides an opportunity to model cell state-fate relationships, revealing a lineage-dependent state diversity within functionally related cells and a winding trajectory of developmental state progression. Collectively, this single-cell protein atlas represents a valuable resource for elucidating metazoan embryogenesis at the molecular and systems levels.

The odd-skipped related gene drumstick is required for leg development in the beetle Tribolium castaneum

BACKGROUND

The evolutionarily conserved odd-skipped related genes odd-skipped (odd), drumstick (drm), sister of odd and bowel (sob), and brother-of-odd-with-entrails-limited (bwl) act downstream of the Notch pathway in various insect tissues including the appendages and the gut. While the function of some of these genes have been analyzed in the adult Tribolium beetle, the expression during and their requirement for embryonic development is not known.

RESULTS

We describe here the embryonic expression patterns of drm, sob, and bwl and analyze the RNAi knockdown phenotypes with emphasize on the appendages and the hindgut. We show that in Tribolium, drm acts independently of other odd-family members in the formation of legs, hindgut, and the dorsal epidermis. Moreover, we establish drm and sob as further markers for segment borders in the appendages that include the gnathobasic mandibles.

CONCLUSIONS

We conclude that the regulatory interrelationship among the odd genes differs between Tribolium and Drosophila, where odd and drm seem to act redundantly. In Tribolium, the genes drm and sob uncover the relict of a precoxal joint incorporated in the lateral body wall.

Odd-skipped related-1 controls neural crest chondrogenesis during tongue development

The tongue is a critical element of the feeding system in tetrapod animals for their successful adaptation to terrestrial life. Whereas the oral part of the mammalian tongue contains soft tissues only, the avian tongue has an internal skeleton extending to the anterior tip. The mechanisms underlying the evolutionary divergence in tongue skeleton formation are completely unknown. We show here that the odd-skipped related-1 (Osr1) transcription factor is expressed throughout the neural crest-derived tongue mesenchyme in mouse, but not in chick, embryos during early tongue morphogenesis. Neural crest-specific inactivation of Osr1 resulted in formation of an ectopic cartilage in the mouse tongue, reminiscent in shape and developmental ontogeny of the anterior tongue cartilage in chick. SRY-box containing gene-9 (Sox9), the master regulator of chondrogenesis, is widely expressed in the nascent tongue mesenchyme at the onset of tongue morphogenesis but its expression is dramatically down-regulated concomitant with activation of Osr1 expression in the developing mouse tongue. In Osr1 mutant mouse embryos, expression of Sox9 persisted in the developing tongue mesenchyme where chondrogenesis is subsequently activated to form the ectopic cartilage. Furthermore, we show that Osr1 binds to the Sox9 gene promoter and that overexpression of Osr1 suppressed expression of endogenous Sox9 mRNAs and Sox9 promoter-driven reporter. These data indicate that Osr1 normally prevents chondrogenesis in the mammalian tongue through repression of Sox9 expression and suggest that changes in regulation of Osr1 expression in the neural crest-derived tongue mesenchyme underlie the evolutionary divergence of birds from other vertebrates in tongue morphogenesis.

odd-skipped related 2 is required for fin chondrogenesis in zebrafish

BACKGROUND

odd-skipped related 2 (osr2) encodes a vertebrate ortholog of the Drosophila odd-skipped zinc-finger transcription factor. Osr2 in mouse is required for proper palate, eyelid, and bone development. Zebrafish knock-down experiments have also suggested a role for osr2, along with its paralog osr1, in early pectoral fin specification and pronephric development.

RESULTS

We show here that osr2 has a specific function later in development, independent of osr1, in the regulation of sox9a expression and promoting fin chondrogenesis. mRNA in situ hybridization demonstrated osr2 expression in the developing floorplate and later during organogenesis in the pronephros and gut epithelium. In the pectoral fin buds, osr2 was specifically expressed in fin mesenchyme. osr2 knock down in zebrafish embryos disrupted both three and five zinc finger alternatively spliced osr2 isoforms and eliminated wild-type osr2 mRNA. osr2 morphants exhibited normal pectoral fin bud specification but exhibited defective fin chondrogenesis, with loss of differentiated chondrocytes. Defects in chondrogenesis were paralleled by loss of sox9a as well as subsequent col2a1 expression, linking osr2 function to essential regulators of chondrogenesis.

CONCLUSIONS

The zebrafish odd-skipped related 2 gene regulates sox9a and col2a1 expression in chondrocyte development and is specifically required for zebrafish fin morphogenesis.

Generation of Osr1 conditional mutant mice

The Odd-skipped related 1 (Osr1) gene encodes a zinc finger protein homologous to the Drosophila Odd-skipped transcription factor. During mouse embryogenesis, Osr1 is expressed in multiple tissues, including the developing heart, kidney, limb, lung, and craniofacial structures. Although characterization of targeted mutant mice has revealed essential roles for Osr1 in heart and kidney development, the embryonic lethality of the Osr1 null mice has hindered investigation of its role in many other developmental processes. We report here the generation of conditional mutant mice containing two loxP sites flanking exon 2 of the Osr1 gene. Mice homozygous for this targeted Osr1( fneo) allele are normal and fertile. Crossing the Osr1(fneo/fneo) mice with the EIIa-Cre transgenic mice resulted in Cre-mediated deletion of the loxP-flanked Exon2 in the germ line and mice homozygous for this deletion recapitulated the Osr1 null mutant phenotypes. The Osr1( fneo) conditional mice will be valuable for tissue-specific analysis of the roles of Osr1 in embryonic and postnatal developmental processes. genesis 49:419-422, 2011.

Functional equivalence of the zinc finger transcription factors Osr1 and Osr2 in mouse development

Osr1 and Osr2 are the only mammalian homologs of the Drosophila odd-skipped family developmental regulators. The Osr1 protein contains three zinc-finger motifs whereas Osr2 exists in two isoforms, containing three and five zinc-finger motifs respectively, due to alternative splicing of the transcripts. Targeted null mutations in these genes in mice resulted in distinct phenotypes, with heart and urogenital developmental defects in Osr1(-/-) mice and with cleft palate and open eyelids at birth in Osr2(-/-) mice. To investigate whether these contrasting mutant phenotypes are due to differences in their protein structure or to differential expression patterns, we generated mice in which the endogenous Osr2 coding region was replaced by either Osr1 cDNA or Osr2A cDNA encoding the five-finger isoform. The knockin alleles recapitulated endogenous Osr2 mRNA expression patterns in most tissues and completely rescued cleft palate and cranial skeletal developmental defects of Osr2(-/-) mice. Mice hemizygous or homozygous for either knockin allele exhibited open-eyelids at birth, which correlated with differences in expression patterns between the knockin allele and the endogenous Osr2 gene during eyelid development. Molecular marker analyses in Osr2(-/-) and Osr2(Osr1ki/Osr1ki) mice revealed that Osr2 controls eyelid development through regulation of the Fgf10-Fgfr2 signaling pathway and that Osr1 rescued Osr2 function in maintaining Fgf10 expression during eyelid development in Osr2(Osr1ki/Osr1ki) mice. These results indicate that the distinct functions of Osr1 and Osr2 during mouse development result from evolutionary divergence of their cis regulatory sequences rather than distinct biochemical activities of their protein products.

C2H2 zinc finger genes of the Gli, Zic, KLF, SP, Wilms' tumour, Huckebein, Snail, Ovo, Spalt, Odd, Blimp-1, Fez and related gene families from Branchiostoma floridae

The C2H2 zinc finger is one of the most common domains encoded by animal genomes and has been implicated in DNA binding as well as protein-protein interactions and RNA binding. Genes encoding C2H2 zinc finger domains include not only well-studied conserved transcription factors such as Gli and Snail but also include a large diversity of more rapidly evolving genes. Here, I focus on the description of amphioxus members of families and super-families of C2H2 zinc finger genes that have been the subject of functional studies in other species, specifically the Gli, Zic, Glis, Snail, Scratch, Krox, Wilms' tumour, Huckebein, SP, KLF, Ovo, Spalt, Blimp-1, Odd and Fez genes. Surveys of the Branchiostoma floridae genome reveal members of all of these groups of genes. Genes are named according to molecular phylogenetic analyses, such that the nomenclature reflects pre-existing gene names in the context of gene families that have descended from a single common ancestral gene in the common ancestor of chordates and insects. In total, this comprises 28 B. floridae C2H2 zinc finger genes, representing at least 15 gene families. For 17 of these genes, expressed sequence tag clusters and associated clone identification codes relating to the B. floridae gene collection are given.

Odd-skipped related 1 gene expression is regulated by Runx2 and Ikzf1 transcription factors

Odd-skipped related 1 (Osr1) gene encodes a zinc-finger transcription factor that plays important roles in embryonic, heart, and urogenital development, however, it is unknown how its expression is regulated. In this study, we analyzed the promoter region of Osr1 to elucidate its regulation mechanism. The mouse Osr1 promoter region was cloned and characterized, and found to have two repressor elements in the -4504/-2766 and -1616/-109 regions, and two enhancer elements in the -2766/-1616 and -109/+199 regions. Several Runx2 and Ikzf1 binding sites were found in both mouse and human Osr1 promoters. Osr1 promoter activity was suppressed by cotransfection with Runx2- and Ikzf1-expressing vectors in a dose-dependent manner. Electrophoresis mobility shift assays showed that purified Runx2 bound to proximal (-611/-606) Runx2 binding motifs and that Ikzf1 bound to proximal (-1652/-1644) Ikzf1 binding motifs. Chrosmatin immunoprecipitation demonstrated that Runx2 bound to both the distal (-3047/-3042) and proximal regions, and that Ikzf1 bound to both the far-distal (-3036/-3028) and proximal elements. These findings indicate that Osr1 expression is regulated by Runx2 and Ikzf1, which are known as master-gene of osteogenesis and hematopoiesis, respectively.

Comparative expression pattern of Odd-skipped related genes Osr1 and Osr2 in chick embryonic development

Odd-skipped genes encode zinc-finger transcription factors with widespread roles in embryonic development. In Drosophila, odd-skipped acts as a pair-rule gene, while its orthologous gene in Caenorhabditis elegans is involved in gut development. In mammals two paralogs exist, Osr1 and Osr2, with functions described in heart and urogenital, and in secondary palate development, respectively. As the chicken embryo is a widely used system for analysing gene function in vivo, we determined the expression pattern of the two chicken orthologues, cOsr1 and cOsr2, during embryonic development. We demonstrate expression of both genes in a variety of organs and structures, such as kidney, eye, branchial arches and dermis. Both genes show a highly dynamic expression pattern with partially overlapping, but mostly distinct domains of expression. Special emphasis in this study was laid on the investigation of cOsr1 and cOsr2 in limb development, where we compared their expression pattern with the expression of Osr1 and Osr2 in the mouse.

Odd-skipped related 1 (Odd 1) is an essential regulator of heart and urogenital development

The Odd-skipped related 1 (Odd 1) gene encodes a zinc finger protein homologous to the Drosophila Odd-skipped class transcription factors that play critical roles in embryonic patterning and tissue morphogenesis. We have generated mice carrying a targeted null mutation in the Odd 1 gene and show that Odd 1 is essential for heart and intermediate mesoderm development. Odd 1(-/-) mutant mouse embryos fail to form atrial septum, display dilated atria with hypoplastic venous valves, and exhibit blood backflow from the heart into systemic veins. In contrast to other transcription factors implicated in atrial septum development, Odd 1 mRNA expression is restricted to the central dorsal domain of the atrial myocardium during normal heart development. Moreover, expression patterns of known key regulatory genes of atrial septum development, including Nkx2.5, Pitx2, and Tbx5, are unaltered in the developing heart in Odd 1(-/-) mutants compared to that of the wild-type littermates. Furthermore, homozygous Odd 1(-/-) mutant embryos exhibit complete agenesis of adrenal glands, metanephric kidneys, gonads, and defects in pericardium formation. Detailed molecular marker analyses show that key regulators of early intermediate mesoderm development, including Lhx1, Pax2, and Wt1, are all down-regulated and nephrogenic mesenchyme undergoes massive apoptosis, resulting in disruption of nephric duct elongation and failure of metanephric induction in the Odd 1(-/-) mutant embryos. These data provide new insights into the molecular mechanisms underlying heart morphogenesis and urogenital development.

Pair rule gene orthologs in spider segmentation

The activation of pair rule genes is the first indication of the metameric organization of the Drosophila embryo and thus forms a key step in the segmentation process. There are two classes of pair rule genes in Drosophila: the primary pair rule genes that are directly activated by the maternal and gap genes and the secondary pair rule genes that rely on input from the primary pair rule genes. Here we analyze orthologs of Drosophila primary and secondary pair rule orthologs in the spider Cupiennius salei. The expression patterns of the spider pair rule gene orthologs can be subdivided in three groups: even-skipped and runt-1 expression is in stripes that start at the posterior end of the growth zone and their expression ends before the stripes reach the anterior end of the growth zone, while hairy and pairberry-3 stripes also start at the posterior end, but do not cease in the anterior growth zone. Stripes of odd-paired, odd-skipped-related-1, and sloppy paired are only found in the anterior portion of the growth zone. The various genes thus seem to be active during different phases of segment specification. It is notable that the spider orthologs of the Drosophila primary pair rule genes are active more posterior in the growth zone and thus during earlier phases of segment specification than most orthologs of Drosophila secondary pair rule genes, indicating that parts of the hierarchy might be conserved between flies and spiders. The spider ortholog of the Drosophila pair rule gene fushi tarazu is not expressed in the growth zone, but is expressed in a Hox-like fashion. The segmentation function of fushi tarazu thus appears to be a newly acquired role of the gene in the lineage of the mandibulate arthropods.