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Y Umesono

Publications and source records attributed to Y Umesono.

7 recordsLinked to original sources
PubMed1999

The planarian HOM/HOX homeobox genes (Plox) expressed along the anteroposterior axis.

In the freshwater planarian Dugesia japonica, five cDNAs for HOM/HOX homeobox genes were cloned and sequenced. Together with sequence data on HOM/HOX homeobox genes of platyhelminthes deposited in databases, comparison of the deduced amino acid sequences revealed that planarians have at least seven HOM/HOX homeobox genes, Plox1 to Plox7 (planarian HOM/HOX homeobox genes). Whole-mount in situ hybridization and RT-PCR revealed that Plox4 and Plox5 were increasingly expressed along a spatial gradient in the posterior region of intact animals. During regeneration, Plox5 was expressed only in the posterior region of regenerating body pieces, suggesting that the gene is involved in the anteroposterior patterning in planarians. Plox5 was not found to be expressed in a blastema-specific manner, which contradicts a previous report (J. R. Bayascas, E. Castillo, A. M. Muños-Mármol, and E. Saló. Development 124, 141-148, 1997). X-ray irradiation experiments showed that Plox5 was expressed at least in some cells other than neoblasts, but that the induction of Plox5 expression during regeneration might require neoblasts.

Amino Acid Sequence↗
PubMed1999

Identification of a photoreceptor cell-specific nuclear receptor.

Nuclear receptors comprise a large and expanding family of transcription factors involved in diverse aspects of animal physiology and development, the functions of which can be modulated in a spatial and temporal manner by access to small lipophilic ligands and/or the specificity of their own localized expression. Here we report the identification of a human nuclear receptor that reveals a unique proximal box (CNGCSG) in the DNA-binding domain. The conservation of this feature in its nematode counterpart suggests the requirement for this type of P box in the genetic cascades mediated by nuclear receptors in a wide variety of animal species. The expression of this receptor, PNR (photoreceptor-specific nuclear receptor), appears strongly restricted in the retina, exclusively in photoreceptor cells. In human cell lines, PNR expression was observed in Y79 retinoblastoma along with other photoreceptor marker genes such as CRX. Among vertebrate receptors, PNR shares structural kinship with an orphan receptor TLX, and despite distinct differences in the DNA binding domain, PNR is able to recognize a subset of TLX target sequences in vitro. Analyses of the human PNR gene revealed its chromosomal position as 15q24, a site that has recently been reported as a susceptible region for retinal degeneration. These data support a role for PNR in the regulation of signalling pathways intrinsic to the photoreceptor cell function.

Amino Acid Sequence↗
PubMed1999

Expression of vasa(vas)-related genes in germline cells and totipotent somatic stem cells of planarians.

Planarians are known for their strong regenerative ability. This ability has been considered to reside in the totipotent somatic stem cell called the "neoblast." Neoblasts contain a unique cytoplasmic structure called the "chromatoid body," which has similar characteristics to the germline granules of germline cells of other animals. The chromatoid bodies decrease in number and size during cytodifferentiation and disappear in completely differentiated cells during regeneration. However, germ cells maintain the chromatoid body during their differentiation from neoblasts. These observations suggest that the chromatoid body is concerned with the totipotency of cells. To understand the molecular nature of the chromatoid body in the neoblast, we focused on vasa (vas)-related genes, since VAS and VAS-related proteins are known to be components of the germline granules in Drosophila and Caenorhabditis elegans. By PCR, two vas-related genes (Dugesia japonica vasa-like gene, DjvlgA and DjvlgB) were isolated, and they were shown to be expressed in germ cells. Interestingly, DjvlgA was also expressed in a number of somatic cells in the mesenchymal space. In regenerating planarians, accumulation of DjvlgA-expressing cells was observed in both the blastema and the blastema-proximal region. In X-ray-irradiated planarians, which had lost regenerative capacity, the number of DjvlgA-expressing cells decreased drastically. These results suggest that the product of DjvlgA may be a component of the chromatoid body and may be involved in the totipotency of the neoblast.

Amino Acid Sequence↗
PubMed1999

Distinct structural domains in the planarian brain defined by the expression of evolutionarily conserved homeobox genes.

Homeobox genes such as orthodenticle in Drosophila and its mouse homologues, Otx1 and Otx2, are known to be essential for rostral brain development. To investigate the molecular basis of brain evolution, we searched for otd/Otx-related homeobox genes in the planarian Dugesia japonica, and identified two genes, DjotxA and B, whose expression appears to be restricted to the cephalic ganglion (brain). DjotxA was expressed more medially, in the region containing the termini of the visual axons, and in the visual cells, suggesting involvement in establishment of the visual system. DjotxB was expressed in a discrete region just lateral to the DjotxA-positive domain, but not in the more lateral branch structures, which in turn are characterized by the expression of Djotp, a planarian homeobox gene related to mouse Orthopedia (Otp). In transverse sections of planarians, DjotxA and B expression were observed only at the anterior ends of the stumps, corresponding to the regional pattern of the regenerating brain. Our findings suggest that the planarian brain is composed of structurally distinct and functionally diverse domains which are defined by the discrete expression of the three evolutionarily conserved homeobox genes.

Amino Acid Sequence↗
PubMed1997

A planarian orthopedia homolog is specifically expressed in the branch region of both the mature and regenerating brain.

To analyze the organization of planarian brain, a homolog of the homeobox-containing gene Orthopedia (Otp) from planarian, Djotp, was isolated. The homeodomain of Djotp differs from mouse Otp by only two amino acids. This conservation extends to include a 12 amino acid motif downstream of the homeodomain. Whole mount in situ hybridization studies indicated that Djotp is specifically expressed in the branch structures of the normal planarian adult brain. During regeneration, Djotp is expressed in the presumptive branch region prior to branch formation. These observations implicate a role for Djotp in establishing and maintaining the identity of the planarian brain branch region. The results suggest that recruitment of Otp for its role in brain pattern formation occurred very early in evolution.

Amino Acid Sequence↗
PubMed1994

Cloning of cDNA for vitellogenin of Athalia rosae (Hymenoptera) and characterization of the vitellogenin gene expression.

Athalia rosae (Hymenoptera) was previously shown to have two vitellins (L-Vn and S-Vn) and the two corresponding vitellogenins (L-Vg and S-Vg). A cDNA expression library was constructed from poly(A)+ RNA prepared from adult female fat body cells, and was screened for the vitellogenins by using antisera against the L- and S-Vn, respectively. Examinations of cloned cDNAs show that the vitellogenin gene is transcribed as a single unit, with the 5'-terminal site coding for the S-Vg and the 3'-terminal site for the L-Vg. Nucleotide sequence at the 5'-end suggests the presence of a 16 amino acid-long signal peptide. Deduced amino acid sequence following the signal peptide shows a complete match with up to the 28 N-terminal amino acid sequence determined on S-Vn. The S-L Vg boundary with deduced amino acid sequence matching with 6 N-terminal amino acid sequence determined on L-Vn is also detected. Northern blot hybridization analysis shows that the vitellogenin gene is expressed in the female fat body as a single 6.5 kb mRNA but not in the ovary, and not in the male fat body. Western blot analysis detects a large precursor polypeptide, reacting with the anti-L-Vn and S-Vn antisera, in the adult female fat body.

Amino Acid Sequence↗