Cloning and chromosome assignment to 1q32 of a human cDNA (RAB7L1) encoding a small GTP-binding protein, a member of the RAS superfamily

A full-length cDNA homologous to RAB7, a member of the RAB-related GTP-binding protein subfamily, was isolated from a human placenta cDNA library. This cDNA, designated RAB7L1, has an open reading frame of 609 nucleotides encoding 203 amino acids. Northern analysis showed that the mRNA is ubiquitously expressed in human tissues, although signal intensities were different among the various organs examined. This gene was located on chromosome band 1q32 by fluorescence in situ hybridization.

Cloning and characterization of two novel human cDNAs (NELL1 and NELL2) encoding proteins with six EGF-like repeats

From a human fetal-brain cDNA library we isolated two novel genes encoding peptides containing six EGF-like repeats. Both showed significant homologies with nel, a gene strongly expressed in neural tissues of chicken. The cDNAs, designated NELL1 (nel-like, type 1) and NELL2 (nel-like, type 2), contained open reading frames encoding 810 and 816 amino acids, respectively. NELL2 is strongly expressed in brain of adult and fetus but only weakly in fetal kidney. NELL1 and NELL2 were mapped by FISH to chromosomal bands 11p15.1-p15.2 and 12q13.11-q13.12, respectively.

Localization of the gustatory pathway in the human midbrain

The localization of the secondary gustatory pathway in the human brainstem still remains uncertain. Here we report two patients with small vascular lesions in the unilateral midbrain tegmentum who presented with taste disturbance on the ipsilateral side of the tongue. In both cases, the dorsomedial mesencephalic tegmental region lateral to the oculomotor nucleus, including the central tegmental tract and the ventral part of the periaqueductal gray, was involved commonly in the lesions. The secondary gustatory pathway arising from the nucleus of the solitary tract appears to run rostrally, without crossing, to the ipsilateral thalamic nucleus through the dorsomedial part of the tegmental region at the rostral level of the midbrain.

Hereditary caeruloplasmin deficiency: clinicopathological study of a patient

A 58 year old patient with dementia, oral dyskinesia, and diabetes mellitus is described. He had an undetectable concentration of serum caeruloplasmin, as an autosomal recessive trait. Brain MRI disclosed a pronounced hypointensity in the bilateral putamina, caudate, and dentate nuclei on both T1 and T2 weighted images. Pathological findings were mainly in those regions of the brain and consisted of neuronal cell loss with gliosis, heavy iron deposition, and spheroids. Visceral organs also had iron deposition, especially severe in the liver and pancreas. The present patient and other recorded cases constitute a clinicopathological entity of hereditary caeruloplasmin deficiency, different from Wilson's disease.

Changes in myocardial lactate metabolism during ramp exercise in patients with effort angina and microvascular angina

Changes in myocardial lactate metabolism during ramp exercise were investigated through great cardiac vein catheterization in 15 patients with effort angina (EA) and 7 patients with microvascular angina (MVA). The exercise test was performed using a supine bicycle ergometer. Blood samples were obtained from the great cardiac vein (GCV) and the radial artery each minute during exercise. Patients in the EA group showed a point at which the lactate extraction ratio (LER) and the ST level decreased rapidly during exercise. This point was clearly recognized in 12 of 13 patients, and may represent the ischemic threshold. Both the LER and ST level showed similar changes during exercise, and these values were significantly different between the ischemic threshold and peak exercise (p < 0.01). Both the LER and ST level were strongly correlated with the duration of exercise until the threshold (r = 0.703). In the MVA group, both the LER and ST level during exercise continuously decreased throughout exercise without an ischemic threshold in all of the subjects. Endomyocardial biopsy revealed sclerosis of small arteries in the myocardium in all of the patients. In both effort angina and microvascular angina, a close correlation was noted between the change in ST and that in the myocardial lactate extraction ratio.

Subcloning of three osteoblastic cell lines with distinct differentiation phenotypes from the mouse osteoblastic cell line KS-4

Three distinct osteoblastic cell lines (KS418, KS460, and KS483) were subcloned from the mouse osteoblastic KS-4 cells, which possessed the abilities not only to differentiate into mature osteoblasts, but also to support osteoclast differentiation in coculture with spleen cells. The order of the magnitude of the basal alkaline phosphatase (ALP) activity was KS483 > KS418 > KS460. KS483 cells were also more differentiated than KS418 and KS460 in terms of ALP activity and osteocalcin production, when cultured in growth medium containing 10% fetal bovine serum. In long-term culture, KS418 and KS483 apparently differentiated into mature osteoblasts and formed calcified nodules without addition of beta-glycerophosphate. Electron microscopic analysis demonstrated that calcification occurring in the nodules was initiated in the matrix vesicles as observed in bone formation in vivo. Nodule formation and mineral deposition occurred simultaneously in the presence of beta-glycerophosphate, but the former always preceded the latter without addition of beta-glycerophosphate. In contrast, KS460 cells did not show time-dependent increases of ALP activity, type I collagen expression and osteocalcin production, which were induced by treatment with recombinant osteogenic protein-1 (OP-1). The three cell lines similarly supported osteoclast differentiation in coculture with spleen cells in response to 1,25-dihydroxyvitamin D3. These results indicate that the three cell lines subcloned from the original KS-4 cells represent phenotypically distinct osteoblasts during osteoblast differentiation, but are equipped similarly with the capacity to support osteoclast differentiation. The subcloned cells of the KS-4 series may provide useful systems in which to study osteoblast differentiation and function.

Selective slow pathway ablation in atrioventricular nodal reentrant tachycardia--comparison of different methods and the site of slow pathway ablation

The optimum potential of the slow pathway (SP) was investigated by determining the effectiveness and safety of high-radiofrequency catheter ablation to treat atrioventricular nodal reentrant tachycardia (AVNRT). The subjects consisted of 29 patients with AVNRT (11 men, with a mean age of 54 +/- 15 years). Three ablation methods were used: a) Method A used the earliest atrial activation site, which is retrograde to the slow pathway, b) Method SP used the SP potential, and c) Method SW, in which ablation was performed stepwise starting from the coronary sinus and moving toward the recording site of the His bundle potential. Five, 20, and 4 patients underwent Methods A, SP, and SW, respectively. The fewest number of applications was needed with Method SP (11 +/- 9, 6 +/- 4, and 13 +/- 9), and the delivered energy was also lowest with Method SP (9151 +/- 6119, 3712 +/- 2168, and 12183 +/- 4090 J, with Methods A, SP, and SW, respectively). In Method SP, the interval between the atrium and SP was significantly longer at sites which cured tachycardia, than at sites at which ablation was ineffective (88 +/- 26 vs 66 +/- 22 msec, p < 0.05). The SP potential showed a humped shape in 18 of 20 patients. Method SP was the most efficient ablation method for treating AVNRT.

Mutations in the BRCA2 gene in hepatocellular carcinomas

To investigate whether the BRCA2 gene plays a role in carcinogenesis of hepatocellular carcinomas or pancreatic cancers in view of frequent losses of heterozygosity on chromosome 13q12-13 in those tumors, we screened the entire coding region of this gene for mutations in 60 hepatocellular carcinomas and 36 pancreatic cancers. No alteration was found in any of the pancreatic cancers examined, but three mutations were identified in hepatocellular carcinomas; one was a 6-bp somatic deletion within intron 6. The other two mutations we identified in hepatocellular carcinomas were missense mutations in the germ line, although all BRCA2 mutations thus far detected in patients with familial breast cancers likewise have been deletions. None of 194 other patients with cancers or 44 normal controls exhibited either mutation. Combined with our demonstration of BRCA2 expression in adult liver tissue, the evidence implies that inactivation of BRCA2 may play some role in development or progression of hepatocellular carcinoma and might predispose carriers of mutant alleles to liver malignancies.

Mitochondrial respiratory impairment in streptozotocin-induced diabetic rat heart

The purpose of this study was to examine mitochondrial respiratory impairment in the diabetic heart. Diabetes mellitus was induced in male Wistar rats by intravenous injection of streptozotocin (STZ) for 2 to 16 weeks (Group D). In some of the diabetic rats, insulin was injected for 2 or 3 weeks prior to sacrifice (Group I). Fasting blood glucose was markedly elevated to greater than 300 mg/dl in Group D and was similar to normal glucose levels in Group I. At 2 weeks after STZ injection, state 3 was only 59.1% of that in the control. Complex I and complex V activities were also significantly reduced to 43.4% and 71.7% of those in the control, respectively. These reductions recovered with insulin treatment. This phenomenon persisted for 16 weeks. Morphological studies revealed swelling of the mitochondria and an increase in lipid droplets in diabetic cardiomyocytes, and these were also improved with insulin treatment. We conclude that in the diabetic heart, disturbance of energy production in cardiac mitochondria is generated by the impairment of oxidative phosphorylation due to depression of complex I and complex V. These changes may contribute the cardiac dysfunction that is a complication of diabetes mellitus.

Dipyridamole suppresses catecholamine- and Ca++ influx-sensitive ventricular arrhythmias

To study the mechanism of ventricular arrhythmias, the effect of dipyridamole (DIP; 300 mg/day), an adenosine transport inhibitor, on ventricular premature contractions (VPCs) was assessed in 12 patients who showed VPCs (21312 +/- 12314/day) on Holter ECG in a controlled setting. The effects were compared with those of verapamil (240 mg/day) and bisoprolol (5 mg/day). DIP suppressed more than one-half the VPCs in 5 patients. The mean degree of reduction in these DIP-responders was 75 +/- 18%. Both verapamil and bisoprolol inhibited VPCs in all of the DIP-responders (verapamil: 71 +/- 15%, bisoprolol: 88 +/- 16%). Two of the 5 DIP-responders had sustained ventricular tachycardias (VT) that were terminated by intravenous DIP, ATP, acetylcholine, verapamil, and propranolol. In contrast, verapamil did not inhibit VPCs in any of the DIP-nonresponders. Bisoprolol also did not suppress VPCs in 3 of 6 DIP-non responders. heart rate was unaffected by DIP, but was suppressed by both verapamil and bisoprolol. In addition, DIP increased the serum concentration of adenosine (control 16.3 +/- 17.1 vs 22.3 +/- 19.0 pmol/ml after DIP, p < 0.05). The inhibitory effect of DIP may involve suppression of Ca+2 current through an extracellular increase in adenosine.

Hematopoietic cell phosphatase, SHP-1, is constitutively associated with the SH2 domain-containing leukocyte protein, SLP-76, in B cells

Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1; previously named HCP, PTP1C, SH-PTP1, and SHP) is a cytosolic protein tyrosine phosphatase that contains two SH2 domains. Recent data have demonstrated that the gene encoding SHP-1 is mutated in motheaten (mc) and viable motheaten (mc') mice resulting in autoimmune disease. More recently, SHP-1 has been shown to negatively regulate B cell antigen receptor (BCR)-initiated signaling. To elucidate potential mechanisms of SHP-1 action in BCR signal transduction, we studied proteins that interact with SHP-1 in B cells. Both anti-SHP-1 antibody and the two SH2 domains of SHP-1 expressed as glutathione S-transferase fusion proteins precipitated at least three phosphoproteins of approximately 75, 110, and 150 kD upon anti-immunoglobulin M stimulation of the WEHI-231 immature B cell line. Binding of SHP-1 to the 75- and 110-kD proteins appeared to be mediated mainly by the NH2-terminal SH2 domain of SHP-1, whereas both the NH2- and COOH-terminal SH2 domains are required for maximal binding to the 150-kD protein. Immunoprecipitation and Western blot analysis revealed that the SHP-1-associated 75-kD protein is the hematopoietic cell-specific, SH2-containing protein SLP-76. Further, this protein-protein association was constitutively observed and stable during the early phase of BCR signaling. However, significant tyrosine phosphorylation of SLP-76 as well as of SHP-1 was observed after BCR ligation. Constitutive association of SHP-1 with SLP-76 could also be detected in normal splenic B cells. Collectively, these results suggest possible mechanisms by which SHP-1 may modulate signals delivered by BCR engagement.

Mutation analysis in the BRCA2 gene in primary breast cancers

Breast cancer, one of the most common and deleterious of all diseases affecting women, occurs in hereditary and sporadic forms. Hereditary breast cancers are genetically heterogeneous; susceptibility is variously attributable to germline mutations in the BRCA1 (ref. 1), BRCA2 (ref. 2), TP53 (ref. 3) or ataxia telangiectasia (ATM) genes, each of which is considered to be a tumour suppressor. Recently a number of germline mutations in the BRCA2 gene have been identified in families prone to breast cancer. We screened 100 primary breast cancers from Japanese patients for BRCA2 mutations, using PCR-SSCP. We found two germline mutations and one somatic mutation in our patient group. One of the germline mutations was an insertion of an Alu element into exon 22, which resulted in alternative splicing that skipped exon 22. The presence of a 64-bp polyadenylate tract and evidence for an 8-bp target-site duplication of the inserted DNA implied that the retrotransposal insertion of a transcriptionally active Alu element caused this event. Our results indicate that somatic BRCA2 mutations, like somatic mutations in the BRCA1 gene, are very rare in primary breast cancers.

Elevated plasma adrenomedullin level in hyperthyroidism

Adrenomedullin is a recently discovered peptide that was first purified from phaeochromocytoma tissue and has marked vasodilatory activity, causing hypotension. In thyrotoxicosis, various haemodynamic changes are observed, including an increase in cardiac output and heart rate with a concomitant decrease in peripheral vascular resistance. To evaluate the mechanism underlying these haemodynamic changes in thyrotoxicosis, we measured the plasma adrenomedullin concentration in thyrotoxic patients with Graves' disease. The plasma concentration of adrenomedullin was elevated in hyperthyroid patients (14.7 +/- 5.7 pmol L-1) compared with euthyroid control subjects (5.6 +/- 1.3 pmol L-1) (P < 0.001). The correlation between the plasma adrenomedullin concentration and serum free thyroid hormone levels was marginally significant. The mean blood pressure was relatively low in the face of an elevated plasma adrenomedullin level. Adrenomedullin may therefore be responsible for the vasodilatation observed in thyrotoxicosis.

Differential regulation of leukocyte function-associated antigen-1/ intercellular adhesion molecules-1-dependent adhesion and aggregation in HL-60 cells

Activation of integrin and organization of cytoskeletal proteins are highly regulated in cell adhesion and aggregation. The interaction of leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecules-1 (ICAM-1) mediates cell adhesion and aggregation, which facilitate leukocyte trafficking to inflamed tissues and augment effector functions. We investigated how LFA-1/ICAM-1-mediated adhesion and aggregation are regulated in HL-60 cells induced to differentiate into neutrophils by retinoic acid (RA). Uninduced HL-60 cells did not bind to ICAM-1 even with stimulation by 12-0-tetradecanoyl phorbol-13-acetate, although they express LFA-1 on the cell surface. When cultured with RA for 24 hours, HL-60 cells were able to adhere to ICAM-1 constitutively. The induction of adhesion did not accompany any change in surface density of LFA-1, indicating that the avidity of LFA-1 was increased. The change in its avidity required de novo synthesis of proteins. Although ICAM-1 was intensely expressed on RA-induced HL-60 cells, these cells did not show any cellular aggregation. The HL-60 cells transfected with the active form of Ras (Val12) exhibited LFA-1/ICAM-1-dependent aggregation by RA stimulation without change in the avidity of LFA-1. In these Ras-transfectants, a cytoskeletal protein, paxillin, was tyrosine-phosphorylated, and the level of F-actin increased. Transforming growth factor (TGF) beta, as well as cytochalasin D, prevented both the tyrosine phosphorylation of paxillin and the aggregation without any effects on the avidity of LFA-1. Thus, an increase in the avidity of LFA-1 was not sufficient for the induction of aggregation, which required activation of Ras and reorganization of cytoskeletal proteins. These results suggest that distinct regulatory mechanisms control LFA-1/ICAM-1-dependent adhesion and aggregation in HL-60 cells differentiating into neutrophils.

Bone morphogenetic protein-12 and -13 inhibit terminal differentiation of myoblasts, but do not induce their differentiation into osteoblasts

Effects of bone morphogenetic protein (BMP)-12 and BMP-13, new members of the BMP family which belong to the transforming growth factor (TGF)-beta superfamily, on terminal differentiation of myoblasts were examined in C2C12 and L-6 myoblasts. When the myoblasts were cultured with BMP-12 or BMP-13, the expression of the myosin heavy chain and the formation of multinucleated myotubes mRNA in L-6 cells. The inhibitory effects of BMP-12 and BMP-13 on myogenic differentiation were similar to the effects of BMP-2, though their potencies were lower than BMP-2. Unlike BMP-2, neither BMP-12 nor BMP-13 induced alkaline phosphatase activity in C2C12 myoblasts. The differences in the biological activities of these new BMPs suggest that the intracellular signalling pathway used by BMP-12 and BMP-13 differs from that of BMP-2.

Lyn and Fgr protein-tyrosine kinases prevent apoptosis during retinoic acid-induced granulocytic differentiation of HL-60 cells

The human promyelocytic leukemia cell line HL-60 can be induced to differentiate toward neutrophils and subsequently die via apoptosis in vitro. In this paper, we investigated the roles of protein-tyrosine kinases (PTKs) in retinoic acid (RA)-induced granulocytic differentiation of HL-60 cells. Accompanying the RA-induced differentiation, activities of src family PTKs Lyn and Fgr became detected and reached a plateau 2 days after the stimulation. The immunoblotting using anti-phosphotyrosine antibody (PY-20) showed that the proteins of 56 and 53 kDa were predominantly tyrosine-phosphorylated at day 2. Adsorption and immunoprecipitation of the cell lysate by specific antibodies evidenced that these phosphotyrosine-containing proteins are Lyn and Fgr PTKs. The degree of both activities and tyrosine phosphorylation of these PTKs was reduced to be minimal at day 5 when the HL-60 cells start to die by apoptosis. The inhibitors of PTKs, herbimycin A and genistein, were demonstrated to cause premature cell death of HL-60 cells in the presence of RA. The death was the consequence of an apoptotic process. The Ra-treated HL-60 cells, when incubated with specific c-lyn or c-fgr antisense oligodeoxynucleotide, also underwent premature death at day 2. These data implicate that Lyn and Fgr PTKs prevent programmed cell death to promote granulocytic differentiation of HL-60 cells.

Isolation of major histocompatibility complex class I cDNA from pink salmon (Oncorhynchus gorbuscha)

An MHC class I cDNA clone was isolated from pink salmon (Oncorhynchus gorbuscha). Eight amino acids, which have been shown in mammals to bind main-chain atoms of peptides, are well conserved in the salmon alpha 1 and alpha 2 domains. Nine amino acids in the alpha 3 domain are classified by Williams and Barclay (Ref. 1. Ann. Rev. Immunol. 6:381-405, 1988) as signature immunoglobulin superfamily residues. The pink salmon MHC class I extracellular domains show 84.2% amino acid identity with those of Atlantic salmon (Sasa p30). polymorphism of the MHC class I alpha 1 domain was determined using PCR with genomic DNA from 12 fish. Sixteen variants were identified with most diversity concentrated in those amino acids that bind directly to peptides in mammalian class I molecules. Non-synonymous substitutions predominate over synonymous ones in the codons encoding these polymorphic residues.

Bone morphogenetic protein-2 does not alter the differentiation pathway of committed progenitors of osteoblasts and chondroblasts

Bone morphogenetic proteins (BMPs) induce cartilage and bone formation at both bony and non-bony sites. We examined the possibility whether BMP-2 induces differentiation of osteoblast progenitors into chondroblast lineage cells using organ culture and cell culture prepared from the calvaria of newborn mouse. BMP-2 stimulated alkaline phosphatase activity (a marker of osteoblasts) and induced positive alcian blue staining (a marker of chondroblasts) in a dose- and time-dependent manner in cell cultures isolated from the whole calvaria. BMP-2 also increased the number of round-shaped cells in the cell cultures, which expressed type II collagen. Histologically, the calvaria consisted of not only bone, but also cartilaginous tissues stained with alcian blue, which were located along the endocranial surface of the parietal and occipital bones. When the calvariae were organ-cultured in the presence of BMP-2, the territory of the cartilaginous tissue was markedly increased, and covered most of the occipital bone. A histological examination of the cultured calvariae showed that the bony region of the occipital bone remained unchanged, while the cartilaginous region expanded independent of the bony region. BMP-2 increased the number of proliferating chondroblasts only in the cartilaginous tissue, but never induced new cartilage formation at the bony site. We obtained cells from the anterior portion that contained no cartilage and the posterior portion which contained cartilage, and we subsequently cultured them separately. BMP-2 stimulated ALP activity in all the cultures. However, the treatment with BMP-2 increased the intensity of alcian blue staining only in tissue culture of the posterior portion, but never induced alcian blue staining in tissue culture of the anterior portion. These results indicate that the chondrocytes induced by BMP-2 were derived from the cartilaginous tissue, which had already formed at the surface of the calvarial bone. BMP-2 did not induce differentiation of committed osteoblast progenitors into chondroblast lineage cells.

Effects of BMP-2, BMP-4, and BMP-6 on osteoblastic differentiation of bone marrow-derived stromal cell lines, ST2 and MC3T3-G2/PA6

The effects of bone morphogenetic protein-2 (BMP-2) on osteoblastic differentiation of bone marrow stromal cells were investigated using two bone marrow stromal cell lines, ST2 and MC3T3-G2/PA6 (PA6). BMP-2 stimulated ALP activity and induced parathyroid hormone (PTH)-dependent production of cAMP in both ST2 and PA6 cells, but these effects were more apparent in ST2 cells than in PA6 cells. BMP-2 induced the production of osteocalcin in ST2 cells, but not in PA6 cells. BMP-4 and BMP-6 stimulated ALP activity in ST2 cells, but the effect of BMP-6 was less marked than that of BMP-2 and BMP-4. BMP-4 induced PTH-dependent cAMP production of cAMP in ST2 cells, but BMP-6 did not. When ST2 cells were transplanted into the peritoneal cavities of athymic mice with BMP-2 in diffusion chambers, these cells generated mineralized bone in the chambers. These results indicate that BMPs induce the differentiation of bone marrow stromal cells into osteoblasts. However, the effects differ among the BMPs and among the types of cell exposed to these proteins.

Immobilized anti-KIT monoclonal antibody induces ligand-independent dimerization and activation of Steel factor receptor: biologic similarity with membrane-bound form of Steel factor rather than its soluble form

Interaction of a tyrosine kinase type receptor and its ligand induces receptor-dimerization or -oligomerization followed by transphosphorylation and activation of its intrinsic kinase, which leads to a series of intracellular signals. We have previously reported that the membrane-bound form of Steel factor (SLF) induces more persistent tyrosine kinase activation and longer life span of c-kit encoded protein (KIT) than its soluble form (Miyazawa et al, Blood 85:641, 1995). In this study, we used YB5.B8 monoclonal antibody (MoAb) that recognizes the extracellular domain of KIT to investigate whether immobilized anti-KIT MoAb can substitute for SLF as a potent activator of KIT by cross-linking receptors and further compared its effect with each SLF isoform in a factor-dependent cell line M07e. YB5.B8 MoAb in a soluble state suppressed SLF-induced M07e cell proliferation in a dose-dependent manner. By contrast, once this antibody was immobilized on the goat-antimouse MoAb (GAM)-coated culture plates, it supported the growth of M07e cells in the absence of any growth factors, whereas culture the cells in GAM alone or YB5.B8 without GAM-coated plates resulted in rapid cell-death within 24 hours. As with the natural ligand SLF, immobilized YB5.B8 MoAb synergized with granulocyte-macrophage colony-stimulating factor (GM-CSF) in inducing cell proliferation compared with either YB5.B8 MoAb or GM-CSF alone. Immunoblotting with antiphosphotyrosine MoAb showed that interaction of M07e cells with immobilized YB5.B8 induced tyrosine phosphorylation of a series of intracellular proteins including KIT (145 kD). In addition, cross-linking studies using a water-soluble cross linking reagent bis-sulfosuccinimidyl-suberate showed that immobilized YB5.B8 MoAb induced dimerization and activation of KIT. However, as with stimulation by the membrane-bound form of SLF, the kinetics of KIT activation with YB5.B8 MoAb was more prolonged compared with the cells treated with recombinant soluble SLF. Flow cytometry showed that, unlike the cells treated with soluble SLF, no downmodulation of cell-surface KIT expression was observed in M07e cells cultured with immobilzed YB5.B8 MoAb. These data suggest that immobilized antibodies against hematopoietic receptors may replace their ligand-stimulators; however, their activities may resemble the membrane-bound form rather than the soluble form of natural ligands.

Molecular cloning of a cDNA encoding diacylglycerol kinase (DGK) in Arabidopsis thaliana

Diacylglycerol kinase (DGK) synthesizes phosphatidic acid from diacylglycerol, an activator of protein kinase C (PKC), to resynthesize phosphatidylinositols. The structure of DGK has not been characterized in plants. We report the cloning of a cDNA, cATDGK1, encoding DGK from Arabidopsis thaliana. The cATDGK1 CDNA contains an open reading frame of 2184 bp, and encodes a putative protein of 728 amino acids with a predicted molecular mass of 79.4 kDa. The deduced ATDGK1 amino acid sequence exhibits significant similarity to that of rat, pig, and Drosophila DGKs. The ATDGK1 mRNA was detected in roots, shoots, and leaves. Southern blot analysis suggests that the ATDGK1 gene is a single-copy gene. The existence of DGK as well as phospholipase C suggests the existence of PKC in plants.

Deposits of eosinophil granule proteins in eosinophilic cholecystitis and eosinophilic colitis associated with hypereosinophilic syndrome

A case of hypereosinophilic syndrome with eosinophilic colitis, eosinophilic cholecystitis, and increased serum levels of interleukin-5 (IL-5) and soluble interleukin-2 receptor (sIL-2R) is reported. Immunohistochemical studies of cholecystectomy and colon biopsy specimens with monoclonal antibodies, which are specific for activated eosinophils, secreted eosinophil cationic protein (ECP) and for major basic protein (MBP), demonstrated the presence of numerous activated eosinophils, secretion of ECP, and deposition of MBP in areas of tissue damage. These findings suggest that in eosinophilic cholecystitis and eosinophilic colitis, activated eosinophils infiltrate and degranulate in each tissue, releasing eosinophil granule proteins that produce tissue damage.

Cloning, expression and chromosome mapping of adducin-like 70 (ADDL), a human cDNA highly homologous to human erythrocyte adducin

From a human fetal-brain cDNA library we isolated a novel human cDNA, termed human adducin-like 70 (gene symbol ADDL), whose predicted amino acid sequence showed a high degree of homology to adducins. This cDNA clone (ADDL), which contained an open reading frame of 2,022 nucleotides encoding 674 amino acids, revealed 54%, 53%, and 59% identity in predicted amino acid sequence with alpha and beta components of human adducin and rat adducin 63, respectively. Human adducin-like 70 is likely to play an important role in the skeletal organization of the cell membrane. Northern blot analysis indicated ubiquitous expression of this gene in adult human tissues. We localized the gene to chromosome bands 10q24.2-->q24.3 by fluorescence in situ hybridization (FISH).