Showing papers by "Nagoya University published in 1995"

Dynamical model of traffic congestion and numerical simulation

Abstract: We present a dynamical model of traffic congestion based on the equation of motion of each vehicle. In this model, the legal velocity function is introduced, which is a function of the headway of the preceding vehicle. We investigate this model with both analytic and numerical methods. The stability of traffic flow is analyzed, and the evolution of traffic congestion is observed with the development of time.

Identification of a Member of the MAPKKK Family as a Potential Mediator of TGF-β Signal Transduction

Abstract: The mitogen-activated protein kinase (MAPK) pathway is a conserved eukaryotic signaling module that converts receptor signals into various outputs. MAPK is activated through phosphorylation by MAPK kinase (MAPKK), which is first activated by MAPKK kinase (MAPKKK). A genetic selection based on a MAPK pathway in yeast was used to identify a mouse protein kinase (TAK1) distinct from other members of the MAPKKK family. TAK1 was shown to participate in regulation of transcription by transforming growth factor-β (TGF-β). Furthermore, kinase activity of TAK1 was stimulated in response to TGF-β and bone morphogenetic protein. These results suggest that TAK1 functions as a mediator in the signaling pathway of TGF-β superfamily members.

Gravitationally redshifted emission implying an accretion disk and massive black hole in the active galaxy MCG-6-30-15

Abstract: ACTIVE galactic nuclei and quasars are probably powered by the accretion of gas onto a supermassive black hole at the centre of the host galaxy1, but direct confirmation of the presence of a black hole is hard to obtain. As the gas nears the event horizon, its velocity should approach the speed of light; the resulting relativistic effects, and a gravitational redshift arising from the proximity to the black hole, should be observable, allowing us to test specific predictions of the models with the observations. Here we report the detection of these relativistic effects in an X-ray emission line (the Kα line) from ionized iron in the galaxy MCG–6–30–15. The line is extremely broad, corresponding to a velocity of ∼100,000 km s−1, and asymmetric, with most of the line flux being redshifted. These features indicate that the line most probably arises in a region between three and ten Schwarzschild radii from the centre, so that we are observing the innermost region of the accretion disk.

Giant magneto-impedance in Co-rich amorphous wires and films

Abstract: A comprehensive analysis of magneto impedance (MI) phenomena in Co-rich amorphous materials is presented on the basis of skin effect in combination with dynamical magnetization processes. We consider a MI effect for which the domain walls are perpendicular to the current and field direction. Thus, the magnetization induced by current proceeds, via both the wall movement and moment rotation. The magnetic responses of impedance in wires and films have some common features and can be understood from the same mechanism. The sensitivity of the magnetic response in a small sample (1 mm length and a few micrometer thickness) is about 10%/Oe in wires and 5%/Oe in films. The model describes well the existing experimental data for moderate frequencies, There is some quantitative discrepancy for the case of a very strong skin effect, where the position dependence of basic magnetostatic parameters is important. >

Hot-Plasma Ejections Associated with Compact-Loop Solar Flares

Abstract: Masuda et al. found a hard X-ray source well above a soft X-ray loop in impulsive compact-loop flares near the limb. This indicates that main energy release is going on above the soft X-ray loop, and suggests magnetic reconnection occurring above the loop, similar to the classical model for two ribbon flares. If the reconnection hypothesis is correct, a hot plasma (or plasmoid) ejection is expected to be associated with these flares. Using the images taken by the soft X-ray telescope aboard Yohkoh, we searched for such plasma ejections in eight impulsive compact-loop flares near the limb, which are selected in an unbiased manner and include also the Masuda flare, 1992 January 13 flare. We found that all these flares were associated with X-ray plasma ejections high above the soft X-ray loop and the velocity of ejections is within the range of 50-400 km s-1. This result gives further support for magnetic reconnection hypothesis of these impulsive compact-loop flares.

Overexpression of a membrane protein, neuropilin, in chimeric mice causes anomalies in the cardiovascular system, nervous system and limbs.

Abstract: Neuropilin is a type 1 membrane protein, which is highly conserved among Xenopus frog, chicken and mouse. The extracellular part of the neuropilin protein is composed of three unique domains, each of which is thought to be involved in molecular and/or cellular interactions. In mice, neuropilin is expressed in the cardiovascular system, nervous system and limbs at particular developmental stages. To clarify the roles of neuropilin in morphogenesis in vivo, we generated mouse embryonic stem (ES) cell clones that constitutively expressed exogenous neuropilin, then produced chimeras using these ES cell clones. The chimeras overexpressed neuropilin and were embryonic lethal. The chimeric embryos exhibited several morphological abnormalities; excess capillaries and blood vessels, dilation of blood vessels, malformed hearts, ectopic sprouting and defasciculation of nerve fibers, and extra digits. All of these abnormalities occurred in the organs in which neuropilin is expressed in normal development. The variety of abnormalities occurring in these chimeric embryos suggested diverse functions of neuropilin in embryonic morphogenesis, which may be ascribed to multiple interaction domains identified in the molecule. Correct spatiotemporal expression of neuropilin seems to be essential for normal development of the cardiovascular system, nervous system and limbs.

Ganglioside GM1 binds to the Trk protein and regulates receptor function

Abstract: Several lines of evidence have suggested that ganglioside GM1 stimulates neuronal sprouting and enhances the action of nerve growth factor (NGF), but its precise mechanism is yet to be elucidated. We report here that GM1 directly and tightly associates with Trk, the high-affinity tyrosine kinase-type receptor for NGF, and strongly enhances neurite outgrowth and neurofilament expression in rat PC12 cells elicited by a low dose of NGF that alone is insufficient to induce neuronal differentiation. The potentiation of NGF activity by GM1 appears to involve tyrosine-autophosphorylation of Trk, which contains intrinsic tyrosine kinase activity that has been localized to the cytoplasmic domain. In the presence of GM1 in culture medium, there is a > 3-fold increase in NGF-induced autophosphorylation of Trk as compared with NGF alone. We also found that GM1 could directly enhance NGF-activated autophosphorylation of immunoprecipitated Trk in vitro. Monosialoganglioside GM1, but not polysialogangliosides, is tightly associated with immunoprecipitated Trk. Furthermore, such tight association of GM1 with Trk appears to be specific, since a similar association was not observed with other growth factor receptors, such as low-affinity NGF receptor (p75NGR) and epidermal growth factor receptor (EGFR). Thus, these results strongly suggest that GM1 functions as a specific endogenous activator of NGF receptor function, and these enhanced effects appear to be due, at least in part, to tight association of GM1 with Trk.

c-kit-dependent development of interstitial cells and electrical activity in the murine gastrointestinal tract.

Abstract: In vivo injection of a neutralizing, monoclonal antibody (ACK2) to the receptor tyrosine kinase (c-kit) disrupts the normal motility patterns of the mouse small intestine. Immunohistochemical studies showed that cells expressing c-kit-like immunoreactivity (c-kit-LI) decreased in numbers in response to ACK2, but the identity of these cells is unknown. We investigated the identity and development of the cells that express c-kit-LI in the mouse small intestine and colon. Cells in the region of the myenteric plexus and deep muscular plexus of the small intestine and in the subserosa, in the myenteric plexus region, within the circular and longitudinal muscle layers, and along the submucosal surface of the circular muscle in the colon were labeled with ACK2. The distribution of cells that express c-kit-LI was the same as that of interstitial cells (ICs). In whole-mount preparations cells with c-kit-LI were interconnected, forming a network similar to the network formed by cells that stained with methylene blue, which has been used as a marker for ICs in the mouse gastrointestinal tract. Immunocytochemistry verified that ICs were labeled with ACK2. Multiple injections of animals with ACK2 between days 0 and 8 post partum (pp) caused a dramatic reduction in the number of ICs compared to control animals. From an ultrastructural point of view, the proliferation and development appeared to be suppressed in some classes of ICs, while others displayed an altered course of development. Functional studies showed that the decrease in ICs was accompanied by a loss of electrical rhythmicity in the small intestine and reduced neural responses in the small bowel and colon. Morphological experiments showed that c-kit-positive cells are ICs, and physiological evidence reinforced the concept that ICs are involved in generation of rhythmicity and translation of neural inputs in gastrointestinal smooth muscles. Controlling the development of ICs provides a powerful new tool for the investigation of the physiological role of these cells.

Confirmation by X-ray diffraction of the endohedral nature of the metallofullerene Y@C82

Abstract: THE synthesis of fullerenes encapsulating various metal atoms within the carbon cage (endohedral metallofullerenes) has stimulated wide interest1,2 because of their unusual structural and electronic properties. Most of the metallofullerenes prepared so far have been based on C82, and have incorporated lanthanum1,3a¤-5, yttrium6,7, scandium8a¤-10 and most of the lanthanide elements11,12′. Although there has been some debate about the endohedral nature of these compounds2,13,14, observations using scanning tunnelling microscopy15,16, extended X-ray absorption fine structure17,18, transmission electron microscopy19 and electron spin resonance3,6a¤-8,10 have strongly suggested that the metal atoms are indeed inside the fullerene cages; theoretical calculations20,21 also indicate that this is the case. But until now, no structural model has been derived experimentally to confirm the endohedral nature of the metallofullerenes. Here we report the results of a synchrotron X-ray powder diffraction study of Y@C82 that confirms that the yttrium atom is located within the carbon cage. The yttrium atom is displaced from the centre of the C82 molecule and is strongly bound to the carbon cage.

A novel dodecadepsipeptide, cereulide, is an emetic toxin of Bacillus cereus

Abstract: A vacuole-formation substance, cereulide of Bacillus cereus, is an emetic toxin in animals. Both oral administration and intraperitoneal injection of cereulide caused dose-dependent emesis in Suncus murinus, a new animal model of emesis. Vagotomy or a 5-HT3 receptor antagonist completely abolished this emetic effect. Therefore, cereulide causes emesis through the 5-HT3 receptor and stimulation of the vagus afferent. We also found that our purified cereulide caused swelling of mitochondria of HEp-2 cells.

Mechanism of activation of the ret proto-oncogene by multiple endocrine neoplasia 2a mutations

Abstract: Transforming activity of the c-ret proto-oncogene with multiple endocrine neoplasia (MEN) 2A mutations was investigated by transfection of NIH 3T3 cells. Mutant c-ret genes driven by the simian virus 40 or cytomegalovirus promoter induced transformation with high efficiencies. The 170-kDa Ret protein present on the cell surface of transformed cells was highly phosphorylated on tyrosine and formed disulfide-linked homodimers. This result indicated that MEN 2A mutations induced ligand-independent dimerization of the c-Ret protein on the cell surface, leading to activation of its intrinsic tyrosine kinase. In addition to the MEN 2A mutations, we further introduced a mutation (lysine for asparaginic acid at codon 300 [D300K]) in a putative Ca(2+)-binding site of the cadherin-like domain. When c-ret cDNA with both MEN 2A and D300K mutations was transfected into NIH 3T3 cells, transforming activity drastically decreased. Western blot (immunoblot) analysis revealed that very little of the 170-kDa Ret protein with the D300K mutation was expressed in transfectants while expression of the 150-kDa Ret protein retained in the endoplasmic reticulum was not affected. This result also demonstrated that transport of the Ret protein to the plasma membrane is required for its transforming activity.

The chemistry and physiological functions of sesame

Abstract: Some historical facts on and botanical descriptions of sesame are given. Some flavor studies of raw and roasted sesame seeds and oils are described. Composition and some usages are also briefly reported. Sesame has long been regarded in the Orient as a health food which increases energy and prevents aging. Sesame oil has been known empirically as a cooking oil which is highly resistant to oxidative deterioration in comparison with other edible oils. Until recently there were no scientific studies to elucidate these interesting aspects of sesame seed and oil, but the author and members of his group initiated studies on the chemical elucidation of antioxidative principles of sesame seed and oil, and extensively investigated the antiaging effect of sesame. Presence of various new antioxidative lignan phenol compounds in sesame seed and oil is described. Sesaminol has been identified as a new antioxidative principle in raw sesame salad oil. The mechanism of the superior antioxidative activity of roas...

A novel integron-like element carrying the metallo-beta-lactamase gene blaIMP.

Abstract: A plasmid-mediated metallo-beta-lactamase gene was cloned from a carbapenem-resistant Serratia marcescens strain, AK9373. The metallo-beta-lactamase gene was identical to the blaIMP, and it was located in the space between an integrase-like gene and an aac(6')-Ib-like gene. The deduced amino acid sequence for the putative integrase gene showed considerable identity (60.9%) to that of the Escherichia coli integrase reported. Sequences similar to the GTTRRRY and an atypical 59-base element containing a 67-bp inverted repeat sequence, which were peculiar to the integrase-dependent recombination, were also conserved in the flanking regions of the blaIMP gene. These findings imply that the metallo-beta-lactamase gene in S. marcescens AK9373 is carried by a novel integron-like element that is mediated by a transferable large plasmid.

The chloroplast genome.

Abstract: The chloroplast genome consists of homogeneous circular DNA molecules. To date, the entire nucleotide sequences (120-190 kbp) of chloroplast genomes have been determined from eight plant species. The chloroplast genomes of land plants and green algae contain about 110 different genes, which can be classified into two main groups: genes involved in gene expression and those related to photosynthesis. The red alga Porphyra chloroplast genome has 70 additional genes, one-third of which are related to biosynthesis of amino acids and other low molecular mass compounds. Chloroplast genes contain at least three structurally distinct promoters and transcribe two or more classes of RNA polymerase. Two chloroplast genes, rps12 of land plants and psaA of Chlamydomonas, are divided into two to three pieces and scattered over the genome. Each portion is transcribed separately, and two to three separate transcripts are joined together to yield a functional mRNA by trans-splicing. RNA editing (C to U base changes) occurs in some of the chloroplast transcripts. Most edited codons are functionally significant, creating start and stop codons and changing codons to retain conserved amino acids.

Antioxidative Activity of Tetrahydrocurcuminoids

Abstract: In order to develop a new type of antioxidative compound which has both the phenolic and β-diketone moiety in the same molecule, we converted three known curcuminoids, curcumin (diferuloylmethane, U1), (4-hydroxy-3-methoxycinnamoyl)methane (U2), and bis-(4-hydroxycinnamoyl)methane (U3), which are the natural antioxidants of Curcuma longa L. (turmeric), to tetrahydrocurcuminoids (THU1, THU2, and THU3, respectively) by hydrogenation, and evaluated their antioxidative activity by using linoleic acid as the substrate in an ethanol/water system. Further, we used the rabbit erythrocyte membrane ghost and rat liver microsome as in vitro systems and determined the antioxidative activity of these curcuminoids. When we evaluated their anti oxidative activity by these assays, it was found that THU1 had the strongest antioxidative activity among all curcuminoids in each assay system. THU1 has been reported to be one of the main metabolites of U1 in vivo [Holder et al., Xenohiotica, 8, 761–768 (1978)]. These results s...

The contribution of plant food antioxidants to human health

Abstract: We have been actively involved in the isolation and characterization of endogenous plant antioxidants that are believed to inhibit lipid peroxidation and offer protection against oxidative damage to membrane functions. Antioxidants have been isolated from conventional food sources, such as tea (green and black), sesame and wild rice, and also from other plant sources, such as rice hulls, and crude plant drugs. Data on new types of water-soluble and lipid-soluble plant antioxidants are provided, and the biological activity and functionality of these antioxidants are discussed.

Observation of ultrahigh gradient electron acceleration by a self-modulated intense short laser pulse.

Abstract: A laser pulse with a power of $\ensuremath{\sim}3$ TW and a duration of 1 ps has been focused onto a gas. Ultrahigh-gradient electron acceleration has been observed in the laser-produced plasma with a density of $\ensuremath{\sim}{10}^{19}$ c${\mathrm{m}}^{\char21{}3}$ when injecting 1 MeV $/c$ electrons. The simulation of the laser-plasma interaction revealed the existence of ultrahigh-gradient wake fields excited due to self-modulation of the laser pulse and its electron acceleration, consistent with the experimental results.

Different sensitivity to wortmannin of two vacuolar sorting signals indicates the presence of distinct sorting machineries in tobacco cells.

Abstract: Vacuolar matrix proteins in plant cells are sorted from the secretory pathway to the vacuoles at the Golgi apparatus. Previously, we reported that the NH2-terminal propeptide (NTPP) of the sporamin precursor and the COOH-terminal propeptide (CTPP) of the barley lectin precursor contain information for vacuolar sorting. To analyze whether these propeptides are interchangeable, we expressed constructs consisting of wild-type or mutated NTPP with the mature part of barley lectin and sporamin with CTPP and mutated NTPP in tobacco BY-2 cells. The vacuolar localization of these constructs indicated that the signals were interchangeable. We next analyzed the effect of wortmannin, a specific inhibitor of mammalian phosphatidylinositol (PI) 3-kinase on vacuolar delivery by NTPP and CTPP in tobacco cells. Pulse-chase analysis indicated that 33 microM wortmannin caused almost complete inhibition of CTPP-mediated transport to the vacuoles, while NTPP-mediated transport displayed almost no sensitivity to wortmannin at this concentration. This indicates that there are at least two different mechanisms for vacuolar sorting in tobacco cells, and the CTPP-mediated pathway is sensitive to wortmannin. We compared the dose dependencies of wortmannin on the inhibition of CTPP-mediated vacuolar delivery of proteins and on the inhibition of the synthesis of phospholipids in tobacco cells. Wortmannin inhibited PI 3- and PI 4-kinase activities and phospholipid synthesis. Missorting caused by wortmannin displays a dose dependency that is similar to the dose dependency for the inhibition of synthesis of PI 4-phosphate and major phospholipids. This is different, however, than the inhibition of synthesis of PI 3-phosphate. Thus, the synthesis of phospholipids could be involved in CTPP-mediated vacuolar transport.

Expression of the betaine aldehyde dehydrogenase gene in barley in response to osmotic stress and abscisic acid

Abstract: When subjected to salt stress or drought, some vascular plants such as barley respond with an increased accumulation of the osmoprotectant glycine betaine (betaine), being the last step of betaine synthesis catalyzed by betaine aldehyde dehydrogenase (BADH). We report here cloning and characterization of BADH cDNA from barley, a monocot, and the expression pattern of a BADH transcript. An open reading frame of 1515 bp encoded a protein which showed high homology to BADH enzymes present in other plants (spinach and sugar-beet) and in Escherichia coli. Transgenic tobacco plants harboring the clone expressed high levels of both BADH protein and its enzymatic activity. Northern blot analyses indicated that BADH mRNA levels increased almost 8-fold and 2-fold, respectively, in leaves and roots of barley plants grown in high-salt conditions, and that these levels decreased upon release of the stress, whereas they did not decrease under continuous salt stress. BADH transcripts also accumulate in response to water stress or drought, indicating a common response of the plant to osmotic changes that affect its water status. The addition of abscisic acid (ABA) to plants during growth also increased the levels of BADH transcripts dramatically, although the response was delayed when compared to that found for salt-stressed plants. Removal of plant roots before transferring the plants to high-salt conditions reduced only slightly the accumulation of BADH transcripts in the leaves.

Plasmid-mediated dissemination of the metallo-beta-lactamase gene blaIMP among clinically isolated strains of Serratia marcescens.

Abstract: The distribution of strains producing metallo-beta-lactamase among 105 strains of Serratia marcescens was investigated. All of these strains were isolated in seven general hospitals located in Aichi Prefecture, Japan, from April to May 1993. Southern hybridization analysis suggested that four S. marcescens strains, AK9373, AK9374, AK9385, and AK9391, had a metallo-beta-lactamase genes similar to the blaIMP gene found by our laboratory (E. Osano, Y. Arakawa, R. Wacharotayankun, M. Ohta, T. Horii, H. Ito, F. Yoshimura, and N. Kato, Antimicrob. Agents Chemother. 38:71-78, 1994), and these four strains showed resistance to carbapenems as well as to the other broad-spectrum beta-lactams. In particular, strains AK9373, AK9374, and AK9391 showed an extraordinarily high-level resistance to imipenem (MICs, > or = 64 micrograms/ml), whereas strain AK9385 demonstrated moderate imipenem resistance (MIC, 8 micrograms/ml). The imipenem resistance of AK9373 was transferred to Escherichia coli CSH2 by conjugation with a frequency of 10(-5). The DNA probe of the blaIMP gene hybridized to a large plasmid (approximately 120 kb) transferred into the E. coli transconjugant as well as to the large plasmids harbored by AK9373. On the other hand, although we failed in the conjugational transfer of imipenem resistance from strains AK9374, AK9385, and AK9391 to E. coli CSH2, imipenem resistance was transferred from these strains to E. coli HB101 by transformation. A plasmid (approximately 25 kb) was observed in each transformant which acquired imipenem resistance. The amino acid sequence at the N terminus of the enzyme purified from strain AK9373 was identical to that of the metallo-beta-lactamase IMP-1. In contrast, strains ES9348, AK9386, and AK93101, which were moderately resistant to imipenem (MICs, > or = 4 to or = 2 micrograms/ml), and strains which showed high-level imipenem resistance because of acquisition of a plasmid-mediated blaIMP-like metallo-beta-lactamase gene had already proliferated as nosocomial infections, at least in a general hospital.

Phenomenological Study of Dynamical Model of Traffic Flow

Abstract: We show that the Car Following Model with Optimal Velocity (Optimal Velocity Model), which was proposed in our previous paper, is a successful traffic model in reproducing the characteristic features of observed traffic flow data In our model the transition from free flow to congested flow occurs spontaneously by the collective motion of vehicles, which obey to the same dynamical equation The observed specific discrepancy of traffic flow vs car density graph is well understood in terms of the phase transition in our model

Spatial and temporal expression of the ret proto-oncogene product in embryonic, infant and adult rat tissues

Abstract: Immunohistochemical analysis with the anti-Ret antibody was performed to investigate the expression of the c-ret proto-oncogene product (c-Ret protein) in embryonic, infant and adult rat tissues. During embryogenesis, the c-Ret expression became detectable by day 11.5 in the developing peripheral and central nervous systems as well as in the excretory system. In the peripheral nervous system of the trunk, it was expressed at high levels in the enteric neuroblasts and the autonomic and dorsal root ganglia. c-Ret positive cells appeared in the mesenchyme around the foregut and the dorsal aorta at day 11.5 and formed the myenteric plexus of the whole embryonic gut and the sympathetic trunk at later stages respectively. Examination of the cranial region revealed that the c-Ret protein was expressed in neural crest cells migrating from rhombomere 4 at day 11.5 and then became positive in the facial, glossopharyngeal and vagus cranial ganglia at day 12.5-13.5. After day 16.5 of gestation, the c-Ret expression was also observed in the trigeminal ganglion. In the central nervous system, the c-Ret protein was expressed in the neuroepithelial cells of the ventral neural tube (day 11.5-14.5), the motor neurons of the spinal cord (day 18.5) as well as in the embryonic neuroretina (day 18.5). In addition to the nervous system, the c-Ret expression was detected in the nephric duct (day 11.5), the ureteric bud (day 13.5) and the collecting ducts of the kidney (day 16.5). After birth, neurons in the nervous systems mentioned above continued to express the c-Ret protein at variable levels while no c-Ret expression was observed in the kidney of adult rats. Furthermore, the c-Ret expression was found in the acinar cells of the salivary gland, the epithelial cells of the thymus and the follicular dendritic cells of the spleen and lymph node in infant and adult rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Properties of the yellow luminescence in undoped GaN epitaxial layers

Abstract: Photoluminescence, time-integrated, time-resolved, and photoluminescence excitation spectroscopy have been employed to study the 2.2 eV (``yellow'') emission in undoped GaN epitaxial layers. It is best described by a recombination model involving shallow donors and deep donors of probably intrinsic origin. Optically detected magnetic resonance reveals the participation of the shallow donor based on the analysis of the g value and Lorentzian line shape.

Misexpression of Hoxa-13 induces cartilage homeotic transformation and changes cell adhesiveness in chick limb buds.

Abstract: During chick limb development, the Abd-B subfamily of genes in the HoxA cluster are expressed in a region-specific manner along the proximodistal axis. To elucidate the function of Hoxa-13 that is expressed in the autopod during normal limb development, Hoxa-13 was misexpressed in the entire limb bud with a replication-competent retroviral system. Misexpression of Hoxa-13 resulted in a remarkable size reduction of the zeugopodal cartilages as a result of the arrest of cartilage cell growth and differentiation restricted in the zeugopod. This size reduction seems to be attributable to homeotic transformation of the cartilages in the zeugopod to the more distal cartilage, that of the carpus/tarsus. This transformation was specific to Hoxa-13 and was not observed by overexpression of other Hox genes. These results indicate that Hoxa-13 is responsible for switching the genetic code from long bone formation to short bone formation during normal development. When the limb mesenchymal cells were dissociated and cultured in vitro, Hoxa-13-expressing limb mesenchymal cells reassociated and were sorted out from nonexpressing cells. Forced expression of Hoxa-13 at the stage that endogenous Hoxa-13 was not expressed as of yet altered the homophilic cell adhesive property. These findings indicate the involvement of Hoxa-13 in determining homophilic cell-to-cell adhesiveness that is supposed to be crucial for the cartilage pattern formation.