Genomic organization and the 5' upstream sequences associated with the specific spatio-temporal expression of HrEpiC, an epidermis-specific gene of the ascidian Halocynthia roretzi

An epidermis-specific gene HrEpiC of the ascidian Halocynthia roretzi is activated in all presumptive blastomeres by the 64-cell stage. To explore the molecular mechanisms underlying the regulation of the timing of activation of HrEpiC, we studied the genomic organization and the 5' upstream sequences of HrEpiC associated with specific spatio-temporal expression of the gene. The restriction site mapping and sequencing of genomic clones showed that the H. roretzi genome contained two copies of HrEpiC gene, HrEpiC1 and HrEpiC2, aligned tandemly in about 8 kb of the genome. Analysis of various deletion constructs with the 5' flanking sequences of HrEpiC1 revealed that 103 bp of the 5' flanking region was sufficient for the minimal epidermis-specific expression of HrEpiC1 and that the region between -281 bp and -198 bp of the 5' flanking region was associated with the amplification of the minimal expression of the reporter gene in the epidermis. This module between -281 bp and -198 bp was also shown to be associated with the timing of the activation of HrEpiC1 by the 64-cell stage. We discussed how the spatio-temporal expression pattern of HrEpiC1 is regulated by the two modules.

Brachyury downstream notochord differentiation in the ascidian embryo

The ascidian tadpole represents the most simplified chordate body plan. It contains a notochord composed of just 40 cells, but as in vertebrates Brachyury is essential for notochord differentiation. Here, we show that the misexpression of the Brachyury gene (Ci-Bra) of Ciona intestinalis is sufficient to transform endoderm into notochord. Subtractive hybridization screens were conducted to identify potential Brachyury target genes that are induced upon Ci-Bra misexpression. Of 501 independent cDNA clones that were surveyed, 38 were specifically expressed in notochord cells. These potential Ci-Bra downstream genes appear to encode a broad spectrum of divergent proteins associated with notochord formation.

Developmental expression of Pax1/9 genes in urochordate and hemichordate gills: insight into function and evolution of the pharyngeal epithelium

The epithelium of the pharynx contributes to the formation of gills in hemichordates, urochordates, cephalochordates and primitive vertebrates, and is therefore a key structure for understanding developmental mechanisms underlying the establishment of chordate body plans. Pax1- and Pax9-related genes encode transcription factors which are expressed in the pharyngeal region of cephalochordates as well as in the vertebrate pharyngeal pouch epithelium that forms the thymus and parathyroid glands. To explore the molecular basis underlying the occurrence and modifications of the pharyngeal epithelium during evolution, we isolated cDNA clones for Pax1- and Pax9-related genes of urochordates (HrPax1/9 of Halocynthia roretzi and CiPax1/9 of Ciona intestinalis) and a hemichordate (PfPax1/9 of Ptychodera flava) from gill cDNA libraries. Each gene is present as a single copy per haploid genome. All of the cDNAs encode typical paired domains and octapeptides but not a homeodomain, as is also true of other Pax1- and Pax9-related genes. Molecular phylogenetic analysis based on comparison of the paired domain amino-acid sequences suggests that HrPax1/9, CiPax1/9 and PfPax1/9 belong to the Pax1/9 subfamily, and that they are descendants of a single precursor of Pax1/Pax9. Screening of HrPax1/9 cDNA clones yielded six different types of transcripts which were generated by alternative splicing. Northern blot, RT-PCR/Southern and in situ hybridization analyses revealed that HrPax1/9, CiPax1/9 and PfPax1/9 are not expressed during early embryogenesis but are expressed in the epithelia of differentiating gills, suggesting that these genes encode gill-specific transcription factors. The Pax1/9 genes therefore might provide the first developmental genetic corroboration of hypotheses of organ-level homology that unifies hemichordates, urochordates and cephalochordates.

An ascidian T-box gene As-T2 is related to the Tbx6 subfamily and is associated with embryonic muscle cell differentiation

The T-box genes, including Brachyury, encode a novel family of transcription factors that play critical roles in various processes of development, in particular, mesoderm formation in chordate embryos. In the case of the ascidian Halocynthia roretzi, the Brachyury (As-T) is expressed exclusively in notochord cells, whereas another T-box gene (As-T2) is expressed in the muscle cells and in the tip of the tail of tailbud embryos. In a previous study, we suggested that the combined pattern of the spatial expressions of As-T and As-T2 appears to correspond to that of a single vertebrate Brachyury gene (Yasuo et al., Dev Biol 1996;180:773-779). The present molecular phylogenetic analysis suggested that As-T2 is a divergent member of the T-box family with a similarity to the Tbx6 subfamily. Vertebrate members of this subfamily are expressed in the posterior paraxial mesoderm, and the mouse Tbx6 is essential for the specification of posterior somite. To investigate the function of As-T2, we examined an ectopic- and/or overexpression of this gene by injecting synthetic mRNA into fertilized eggs. The results showed that the injection of As-T2 mRNA induced an ectopic expression of muscle-specific myosin heavy-chain gene and actin gene, especially in presumptive epidermal cells. This ectopic muscle-specific expression was accompanied by the partial suppression of an epidermis-specific gene expression. The overexpression of As-T2, however, rarely affected the expression of As-T (Brachyury) and genes that are expressed in the tailbud.

Growth inhibition of human osteosarcoma HuO9 cells by methylglyoxal bis(cyclopentylamidinohydrazone) in vitro and in vivo

Polyamines are considered to be important intracellular molecules for the proliferation of cancer cells. In this study, effects of methyl-glyoxal bis(cyclopentylamidinohydrazone) (MGBCP), a potent inhibitor of the polyamine biosynthetic pathway, on the growth of human osteosarcoma HuO9 cells have been investigated. MGBCP dose-dependently inhibited the growth of HuO9 cells, in which the contents of spermine, spermidine and putrescine decreased concomitantly. The MGBCP-treated cells clearly exhibited morphological changes, indicating the blebbing and chromatin condensation which are characteristic of apoptosis. Characteristic oligonucleosomal-sized DNA fragments were observed in the MGBCP-treated cells. In in vivo experiments MGBCP (20 or 50 mg/kg) inhibited the growth of transplanted HuO9 tumors in mice. These findings suggest that the inhibition of polyamine synthesis results in the suppression of growth of osteosarcoma HuO9 cells, eventually inducing apoptosis in these human osteosarcoma cells in vitro and in vivo.

Effects of qing fei tang (TJ-90) on aspiration pneumonia in mice

The effects of Qing Fei Tang (Sei-hai To in Japanese), a Chinese traditional medical mixture, on aspiration pneumonia were studied using mice inoculated with both Streptococcus pneumoniae and gastric juice as aspiration pneumoniae models. Daily (4 weeks) oral usage of Qing Fei Tang before inoculation reduced remarkably the mortality rate of mice. In this aspiration pneumonia model, xanthine oxidase (XO) activity in the lung tissues was elevated, but this elevation was remarkably decreased by use of Qing Fei Tang. These results suggest that Qing Fei Tang pretreatment can reduce oxygen radical production in inflammed lungs and may reduce the mortality for aspiration pneumonia.

[Surgical removal of large cavernous angioma in the pontomedullary junction: a case report]

Recent advances in neuroradiology have enabled us to approach cavernous angioma in the brain stem. A case of large cavernous angioma, which was located in the pontomedullary junction, was removed surgically. A 24-year-old female was admitted with occipitalgia, dizziness, nausea, gait disturbance. On neurologic examination, the patient had right hemiparesis, slight right facial palsy and paresthesia, right hemiparesthesia, dysphagia. T1 weighted Gd enhanced MRI revealed a mixed intensity lesion. These findings were thought to be consistent with a cavernous angioma. Follow up MRI findings demonstrated progressive increase in cavernous angioma. Vertebral angiograms showed a mass sign and a venous angioma in the midline of the pontomedullary junction. Therefore, the operation was performed in an attempt to remove the cavernous angioma through the midline of the fouth ventricle. The operation was performed under monitoring of electromyogram of facial muscle and external ocular muscle. The cavernous angioma was removed totally, and addition neurogical deficits were minimal.

Pattern of Brachyury gene expression in starfish embryos resembles that of hemichordate embryos but not of sea urchin embryos

Echinoderms, hemichordates and chordates are deuterostomes and share a number of developmental features. The Brachyury gene is responsible for formation of the notochord, the most defining feature of chordates, and thus may be a key to understanding the origin and evolution of the chordates. Previous studies have shown that the ascidian Brachyury (As-T and Ci-Bra) is expressed in the notochord and that a sea urchin Brachyury (HpTa) is expressed in the secondary mesenchyme founder cells. A recent study by [Tagawa et al. (1998)], however, revealed that a hemichordate Brachyury (PfBra) is expressed in a novel pattern in an archenteron invagination region and a stomodaeum invagination region in the gastrula. The present study demonstrated that the expression pattern of Brachyury (ApBra) of starfish embryos resembles that of PfBra in hemichordate embryos but not of HpTa in sea urchin embryos. Namely, ApBra is expressed in an archenteron invagination region and a stomodaeum invagination region.

Identification and characterization of maternally expressed genes with mRNAs that are segregated with the endoplasm of early ascidian embryos

Endoderm cells of the ascidian embryo are specified autonomously dependent on maternal cytoplasmic information or determinants that are localized in the endoplasm. In the present study, we identified three maternally expressed genes (CsEndo-1, CsEndo-2 and CsEndo-3) by screening a cDNA library of Ciona savignyi fertilized egg mRNAs subtracted with gastrula mRNAs. CsEndo-1 encoded a protein with nuclear localization signals, CsEndo-3 predicted a protein containing both a potential transmembrane domain and the PDZ domain, and CsEndo-2 suggested a protein with no similarity to known proteins. The maternal transcripts of all of these genes were not concentrated during early stages of embryogenesis up to the 8-cell stage, but were concentrated at the endoplasmic region by the 16-cell stage and then segregated later with the endoplasm. At the 110-cell stage, the maternal transcript of CsEndo-1 was evident only in the primordial endoderm cells, while those of CsEndo-2 and CsEndo-3 were found in the primordial endoderm cells as well as the primordial notochord cells. All of the transcripts became barely detectable during gastrulation and neurulation. Later, zygotic expression of the three genes became evident again in the endoderm and notochord cells, suggesting developmental roles in the formation of these types of cell. Although we were not able to deduce their functions, this is the first report of maternal genes with mRNAs that are segregated with the endoplasm of ascidian embryos.

Plasma platelet-activating factor acetylhydrolase deficiency in Japanese patients with asthma

Platelet-activating factor (PAF), a phospholipid with a wide range of proinflammatory actions, is immediately degraded and inactivated in vivo by PAF acetylhydrolase (PAF-AH). Surprisingly, 4% of the Japanese population lacks the extracellular isoform of this enzyme, plasma PAF-AH, due to a genetic missense (V279F) mutation. We studied the association of this mutation with asthma prevalence and phenotypes in the Japanese adult population. The allele frequency of V279F mutation was 18.6% in 279 patients with asthma (28.7% heterozygotes and 4.3% homozygotes) and 21.7% in 217 healthy subjects (32.3% heterozygotes and 5.5% homozygotes). V279F mutant allele prevalence was consistent regardless of asthma type (16.3% in atopic [n = 156] and 21.6% in nonatopic [n = 123]), or the severity of disease (21.7% in patients with mild [n = 97], 17.5% in those with moderate [n = 131], and 15.8% in those with severe [n = 51] asthma). Plasma PAF-AH activity was inversely proportional to the number of mutant alleles, and did not correlate with asthma prevalence, type, or severity. We concluded that plasma PAF-AH deficiency due to V279F mutation is not essential to the pathophysiology of asthma in the Japanese adult population.

Genomic organization and evolution of actin genes in the amphioxus Branchiostoma belcheri and Branchiostoma floridae

We previously described the cDNA cloning and expression patterns of actin genes from amphioxus Branchiostoma floridae (Kusakabe, R., Kusakabe, T., Satoh, N., Holland, N.D., Holland, L.Z., 1997. Differential gene expression and intracellular mRNA localization of amphioxus actin isoforms throughout development: implications for conserved mechanisms of chordate development. Dev. Genes Evol. 207, 203-215). In the present paper, we report the characterization of cDNA clones for actin genes from a closely related species, Branchiostoma belcheri, and the exon-intron organization of B. floridae actin genes. Each of these two amphioxus species has two types of actin genes, muscle and cytoplasmic. The coding and non-coding regions of each type are well-conserved between the two species. A comparison of nucleotide sequences of muscle actin genes between the two species suggests that a gene conversion may have occurred between two B. floridae muscle actin genes BfMA1 and BfMA2. From the conserved positions of introns between actin genes of amphioxus and those of other deuterostomes, the evolution of deuterostome actin genes can be inferred. Thus, the presence of an intron at codon 328/329 in vertebrate muscle and cytoplasmic actin genes but not in any known actin gene in other deuterostomes suggests that a gene conversion may have occurred between muscle and cytoplasmic actin genes during the early evolution of the vertebrates after separation from other deuterostomes. A Southern blot analysis of genomic DNA revealed that the amphioxus genome contains multiple muscle and cytoplasmic actin genes. Some of these actin genes seem to have arisen from recent duplication and gene conversion. Our findings suggest that the multiple genes encoding muscle and cytoplasmic actin isoforms arose independently in each of the three chordate lineages, and gene duplications and gene conversions established the extant actin multigene family during the evolution of chordates.

A comparative molecular approach to mesodermal patterning in basal deuterostomes: the expression pattern of Brachyury in the enteropneust hemichordate Ptychodera flava

This work concerns the formation of mesoderm in the development of an enteropneust hemichordate, Ptychodera flava, and the expression of the Brachyury gene during this process. Brachyury expression occurs in two distinct phases. In the embryo, Brachyury is transcribed during gastrulation in the future oral and anal regions of the gut, but transcripts are no longer detected by 2 weeks of development. Brachyury expression is not detected during the 5 months of larval planktonic existence. During this time, the adult coeloms begin to develop, originating as coalescences of cells that appear to delaminate from the wall of the gut. Brachyury expression cannot be detected again until metamorphosis, when transcripts appear in the mesoderm of the adult proboscis, collar and the very posterior region of the trunk. It is also expressed in the posterior end of the gut. At no time is Brachyury expressed in the stomochord, the putative homologue of the chordate notochord. These observations illuminate the process of maximal indirect development in Ptychodera and, by comparison with patterns of Brachyury expression in the indirect development of echinoderms, their sister group, they reveal the evolutionary history of Brachyury utilization in deuterostomes.

The mitochondrial genome of the hemichordate Balanoglossus carnosus and the evolution of deuterostome mitochondria

The complete nucleotide sequence of the mitochondrial genome of the hemichordate Balanoglossus carnosus (acorn worm) was determined. The arrangement of the genes encoding 13 protein, 22 tRNA, and 2 rRNA genes is essentially the same as in vertebrates, indicating that the vertebrate and hemichordate mitochondrial gene arrangement is close to that of their common ancestor, and, thus, that it has been conserved for more than 600 million years, whereas that of echinoderms has been rearranged extensively. The genetic code of hemichordate mitochondria is similar to that of echinoderms in that ATA encodes isoleucine and AGA serine, whereas the codons AAA and AGG, whose amino acid assignments also differ between echinoderms and vertebrates, are absent from the B. carnosus mitochondrial genome. There are three noncoding regions of length 277, 41, and 32 bp: the larger one is likely to be equivalent to the control region of other deuterostomes, while the two others may contain transcriptional promoters for genes encoded on the minor coding strand. Phylogenetic trees estimated from the inferred protein sequences indicate that hemichordates are a sister group of echinoderms.

Characterization of an ascidian maternal T-box gene, As-mT

The T-box genes encode a novel family of transcriptional factors that seem to play crucial roles in various processes of animal development, in particular, mesoderm formation of chordate embryos. The ascidian egg has been regarded as a typical mosaic egg, in which several types of embryonic cells are specified autonomously dependent on prelocalized maternal factors or determinants. In the present study, we investigated a possible role of a maternal T-box gene (As-mT) of the ascidian Halocynthia roretzi. A cDNA clone we obtained predicted As-mT protein of 891 amino acids with a distinct T-domain, which was divergent from those of other T-box genes. Expression of As-mT was exclusively maternal. Although the transcript became barely detectable by the gastrula stage, no zygotic expression was evident during embryogenesis. The maternal transcript was distributed rather evenly within eggs and early embryos without any special localization. Injection of synthetic As-mT mRNA into fertilized eggs induced retardation of embryogenesis. Although cleavage occurred normally, the initiation of gastrulation was delayed, and delay in the morphogenesis resulted in dumpy larvae. Expression of a muscle-specific actin gene, a notochord-specific Brachyury gene, and an epidermis-specific gene was not detected at the early gastrula stage, all of the three genes being expressed in normal embryos at that stage. However, the expression of these genes as well as a mesenchyme-specific gene and histochemical activity of endoderm-specific alkaline phosphatase were evident by the mid-tailbud stage.

Regulation of the trunk-tail patterning in the ascidian embryo: a possible interaction of cascades between lithium/beta-catenin and localized maternal factor pem

Embryonic cell specification and pattern formation in the ascidian embryo are controlled by prelocalized egg cytoplasmic determinants. In previous studies, we showed that overexpression of a maternal gene, posterior end mark (pem), whose transcript localizes to posterior-vegetal cytoplasm of the fertilized egg, causes a loss of the anterior and dorsal structures of the larva (Yoshida et al., Development 122, 2005-2012, 1996). In the present study, first we observed that lithium treatment resulted in reduction of the larval tail. Lineage tracing analyses revealed that descendants of the A4.1 blastomere of the 8-cell-stage embryo (which forms the greater part of notochord and nerve cord) were missing from the tail region, that they were translocated anteriorly into the trunk region, and that the fate of the A4.1-line notochord cells had changed to endoderm. These results suggest that lithium treatment affects the trunk-tail patterning during embryogenesis by changing the cell fate of specific cell lineages. Second, we showed that lithium treatment could rescue the anterior and dorsal structures in pem-overexpressed larvae. This result suggests that pem plays a role in the patterning of the ascidian embryo via a signaling cascade that is affected by lithium. Third, we isolated an ascidian beta-catenin gene and found that overexpression of beta-catenin in the A4.1 blastomere had effects very similar to lithium treatment, such as reduction of the tail and anterior translocation of A4.1 descendants. These results suggest that the target of lithium is, at least in part, the Wnt-signaling cascade and that pem may also function via this cascade.

Recurrent varicella-zoster virus retinitis in a patient treated with systemic corticosteroids

A case of recurrent unilateral varicella-zoster virus (VZV) retinitis is reported. The retinitis was characterized by arteriolitis and retinal necrosis with secondary chorioretinal atrophy localized in the periphery of the supratemporal quadrant of the retina. Polymerase chain reaction analysis of aqueous humor demonstrated VZV DNA in both the initial and recurrent episode. The Goldmann-Witmer coefficient for VZV IgG was elevated. The initial VZV retinitis was successfully treated with acyclovir and corticosteroids. Three years later, high-dose corticosteroids alone were used to treat idiopathic facial nerve palsy. One month after concluding corticosteroids therapy, the VZV retinitis recurred in the same eye, suggesting that administration of the high-dose corticosteroids caused VZV reactivation and induced recurrence of VZV retinitis.

Conservation of the developmental role of Brachyury in notochord formation in a urochordate, the ascidian Balocynthia roretzi

The notochord is one of the characteristic features of the phylum Chordata. The vertebrate Brachyury gene is known to be essential for the terminal differentiation of chordamesoderm into notochord. In the ascidian, which belongs to the subphylum Urochordata, differentiation of notochord cells is induced at the late phase of the 32-cell stage through cellular interaction with adjacent endoderm cells as well as neighboring notochord cells. The ascidian Brachyury gene (As-T) is expressed exclusively in the notochord-lineage blastomeres, and the timing of gene expression at the 64-cell stage precisely coincides with that of the developmental fate restriction of the blastomeres. In addition, experimental studies have demonstrated a close relationship between the inductive events and As-T expression. In the present study, we show that overexpression of As-T by microinjection of the synthesized As-T RNA results in the occurrence, without the induction, of notochord-specific features in the A-line presumptive notochord blastomeres. We also show that overexpression of As-T RNA leads to ectopic expression of notochord-specific features in non-notochord lineages, including those of spinal cord and endoderm. These results strongly suggest that the developmental role of the Brachyury is conserved throughout chordates in notochord formation.

6-Phosphogluconate dehydrogenase is a 45-kDa antigen recognized by S4D5, a monoclonal antibody specific to vanadocytes in the vanadium-rich ascidian Ascidia sydneiensis samea

We previously prepared a monoclonal antibody, S4D5, specific to vanadocytes, vanadium-containing blood cells, in the vanadium-rich ascidian Ascidia sydneiensis samea. Here, we demonstrate that a 45-kDa antigen recognized by S4D5 is 6-phosphogluconate dehydrogenase (6-PGDH), an enzyme of the pentose phosphate pathway, based on cDNA isolation of RNA samples from blood cells of the ascidian. Western blot analysis confirmed an abundance of 6-PGDH protein in the vanadocytes and localization of 6-PGDH in the soluble extract of the blood cells. Soluble protein exhibited a correspondingly high level of 6-PGDH enzymatic activity. Ascidians are known to selectively accumulate high levels of vanadium in vanadocytes, and the highest recorded concentration of accumulated vanadium is 350 mM, which is 10(7) times the concentration in sea water. Almost all vanadium ions are reduced to the +3 oxidation state via the +4 oxidation state in vanadocytes, indicating that reducing agents must participate in the accumulation. On the other hand, vanadium ions in the +5 oxidation state are reduced to the +4 oxidation state by the presence of NADPH in vitro. Together, these observations suggest that NADPH produced in the pentose phosphate pathway may conjugate the reduction of vanadium from the +5 oxidation state through the +4 oxidation state in vanadocytes of ascidians.

Isolation and characterization of endostyle-specific genes in the ascidian Ciona intestinalis

The endostyle is a special organ in the pharynx of Urochordata, Cephalochordata, and Cyclostomata. It may have arisen in the common ancestor of these taxa, along with a shift to internal feeding for extracting suspended food from the water. In addition, the endostyle has a functional homology to the vertebrate thyroid gland. The endostyle is therefore one of the structures key to the understanding of the origin and evolution of chordates. In the present study, we isolated and characterized cDNA clones for four endostyle-specific genes, CiEnds1, CiEnds2, CiEnds3, and CiEnds4, of the ascidian Ciona intestinalis. Although the predicted amino acid sequences of the gene products CiENDS1, CiENDS2, and CiENDS3 showed no similarity to known proteins, their mean hydropathy profiles suggest that they are secretory proteins. In addition, CiENDS3 contained a unique repeat of 10 amino acids [R(QPCI)-(RRPC)I]. CiEnds1 and CiEnds2 were expressed in zone 6, a protein-secreting glandular element of the endostyle, and CiEnds3 was expressed in zone 2, another secretory zone. CiEnds4, a cytoplasmic actin gene, was predominantly expressed in zones 3 and 5, which are supporting elements of the endostyle. The amino acid sequences of CiENDS1 and CiENDS2 resembled each other. In addition, they resembled a zone-6-specific gene product (HrENDS2) of another ascidian, Halocynthia roretzi. The results suggest that these genes are conserved among ascidian species, and therefore they (as well as CiEnds3 for the protein with a unique motif) may be useful probes for further analyses of molecular mechanisms involved in endostyle development.

An ascidian gene encoding an SH2-domain protein is expressed in the notochord cells of the embryo

Differentiation of notochord cells in the ascidian embryo requires cell-cell interactions and signal transduction pathways. Isolation and characterization of an ascidian gene (HrSH2) from Halocynthia roretzi is reported. Sequence analysis suggests that HrSH2 encodes a polypeptide with an SH2 domain and a tyrosine kinase phosphorylation site, that are implicated in signaling pathways through tyrosine phosphorylation. Zygotic expression of HrSH2 was transient. The gene expression began at the 110-cell stage but was downregulated by the larval stage. Whole-mount in situ hybridization, taking advantage of well-known lineage, revealed that the HrSH2 transcript first appeared in primordial notochord cells as well as a few endoderm cells of the 110-cell embryo. During gastrulation and neurulation, expression in the endoderm was downregulated, and instead HrSH2 transcript became evident in notochord cells, nerve cord cells, endodermal strand cells and epidermal cells of the tail. These results suggest the possibility that HrSH2 is involved in the signal transduction pathways required for notochord formation and for differentiation of other cells in conjunction with the notochord.

Novel pattern of Brachyury gene expression in hemichordate embryos

Together with echinoderms and chordates, hemichordates constitute the third major group of the deuterostomes, which share a number of common developmental features. The Brachyury gene is responsible for the formation of notochord, the most defining feature of chordates. Therefore, isolation and characterization of the hemichordate homolog of Brachyury is key to understand the origin and evolution of chordates. Here we show that the hemichordate Brachyury gene (PfBra) is expressed in two regions of the gastrula and young tornaria larva, the archenteron invagination region and the stomodeum invagination region.

Analysis of uveitogenic sites in phosducin molecule

PURPOSE

Phosducin, a retinal photoreceptor protein, induces experimental autoimmune uveitis (EAU). In this study, we attempted to determine the numbers of uveitogenic sites in phosducin using synthetic peptides.

METHODS

Antigen peptides were synthesized according to the amino acid sequence of the rat-derived phosducin with a peptide-synthesizer and purified by reversed-phase HPLC. First, 13 peptides covering the entire sequence of phosducin were synthesized, and each was injected into the hind footpad of Lewis rats for immunization, and induction of EAU was examined clinically and histologically. Next, peptides that appeared to contain sequences of a uveitogenic site were newly synthesized and examined clinically and immunologically.

RESULTS

Of the 13 peptides used in the first immunization, 7 induced inflammation. Similar to other EAU antigens, clinical changes began with fibrin deposition in the anterior segment and posterior synechia, followed by posterior chamber hypopyon. Histologically, inflammation was observed mainly in the outer segment of photoreceptor cells and outer nuclear layer, and serous retinal detachment was found in cases of severe inflammation. Infiltration of inflammatory cells in the pineal gland was also observed. In experiments designed to further specify the uveitogenic sites, the presence of inflammation-inducing sequences was inferred for amino acid sequences 1-20, 23-37, 79-91, 127-142 and 198-212. The rats immunized with these peptides also exhibited high value on lymphocyte proliferation assay.

CONCLUSION

Phosducin has 5 uveitogenic sites. Among others, one of them has potent and others weak uveitogenicity.