Molecular cloning of a homologue of dad-1 gene in citrus: distinctive expression during fruit development

A cDNA homologue to the human defender against apoptotic death gene (dad-1), which is involved in programmed cell death, was isolated from satsuma mandarin (Citrus unshiu Marc.) fruit. It (Citdad-1-1) was 345 bp long, with a deduced protein sequence of 115 amino acids. Southern hybridization suggests that dad-1-related sequences are present as a small gene family in the citrus genome. Expression of Citdad-1-1 was progressively down-regulated in leaves as they matured, but not in juice sac/segment epidermis (edible part) towards fruit ripening. The role of dad-1 during citrus development is also discussed.

Distinct domains of mouse dishevelled are responsible for the c-Jun N-terminal kinase/stress-activated protein kinase activation and the axis formation in vertebrates

Recent studies have shown that Drosophila Dishevelled (Dsh), an essential component of the wingless signal transduction, is also involved in planar polarity signaling through the c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) pathway in Drosophila. Here, we show that expression of a mouse homolog of Dsh (mDvl-1) in NIH3T3 cells activates JNK/SAPK, and its activator MKK7. A C-terminal half of mDvl-1 which contains the DEP domain was sufficient for the activation of JNK/SAPK, whereas an N-terminal half of mDvl-1 as well as the DEP domain is required for stimulation of the TCF/LEF-1-dependent transcriptional activation, a beta-catenin-dependent process. A single amino acid substitution (Met for Lys) within the DEP domain (mDvl-1 (KM)) abolished the JNK/SAPK-activating activity of mDvl-1, but did not affect the activity to activate the LEF-1-dependent transcription. Ectopic expression of mDvl-1 (KM) or an N-terminal half of mDvl-1, but not the C-terminal, was able to induce secondary axis in Xenopus embryos. Because the secondary axis formation is dependent on the Wnt/beta-catenin signaling pathway, these results suggest that distinct domains of mDvl-1 are responsible for the two downstream signaling pathways, the beta-catenin pathway and the JNK/SAPK pathway in vertebrates.

Activation of the protein kinase ERK5/BMK1 by receptor tyrosine kinases. Identification and characterization of a signaling pathway to the nucleus

ERK5 (also known as BMK1), a member of the mitogen-activated protein kinase (MAPK) superfamily, was known to be activated strongly by oxidant and osmotic stresses. Here we have found that ERK5 is strongly activated by epidermal growth factor and nerve growth factor, whose receptors are tyrosine kinases. The activation of ERK5 was inhibited by expression of dominant-negative Ras and induced by expression of active Ras in PC12 cells, indicating a requirement for Ras in ERK5 activation. The epidermal growth factor-induced activation of ERK5 was found to be inhibited by PD98059 and U0126 inhibitors, which were previously thought to act specifically on classical MAPK kinase (also known as MEK1) and readily reversed by CL100 and MKP-3 dual-specificity phosphatases for which classical MAPKs were previously shown to serve as preferred substrates. The reporter assays demonstrated that the serum-induced enhancement of transcription from serum response element was significantly inhibited by expression of a dominant-negative form of MEK5, which was a direct and specific activator for ERK5 and that transcription from serum response element mediated by the Ets-domain transcription factor Sap1a, but not by Elk1, was stimulated by coexpression of ERK5 and active MEK5. In addition, Sap1a was shown to be phosphorylated by ERK5 in vitro and by the activation of the ERK5 pathway in cells. Moreover, the serum-induced c-Fos expression was markedly inhibited by expression of dominant-negative MEK5. These results reveal a novel signaling pathway to the nucleus mediated by ERK5 that functions downstream of receptor tyrosine kinases to induce immediate early genes, in parallel with the classical MAPK cascade.

[Supramicrosurgical lymphaticovenular anastomosis for the treatment of lymphedema in the extremities]

During the past eight years, we treated obstructive lymphedema of a unilateral upper extremity in 27 females and of a unilateral or bilateral lower extremity in 35 males and females with supramicrosurgical lymphaticovenular anastomoses and/or conservative treatment. The most common cause of upper limb edema was mastectomy with or without subsequent radiation therapy for breast cancer, and that of lower limb edema was hysterectomy with radiation. As an objective assessment of edema, the circumferences of the affected and opposite normal forearms or lower legs were measured 10 cm below the olecranon of the arm or the lower border of the patella. In patients who received conservative treatment (12 arms and 12 legs), the average excess circumferential length of the affected arm and leg was 6.4 and 7.1 cm over that of normal extremities, average duration of edema before treatment was 3.5 and 5.2 years, average period for conservative treatment was 10.6 months and 1.5 years, and average decreased circumferential length was 0.8 and 0.6 cm, respectively. The rate of circumferential decrease over 4 cm was none in arm and 16.7% in leg edema. In patients who underwent surgery (12 arms and 16 legs), the average excess circumferencial length was 8.9 and 9.8 cm, average duration of edema before surgery was 8.2 and 8.9 years, average follow-up after surgery was 2.2 and 3.3 years, and average decrease in excess circumference was 4.1 and 2.7 cm, respectively. The rate of circumferential decrease over 4 cm was 58.3% in arms and 50% in legs. These results indicate that supramicrolymphaticovenular anastomoses have a valuable place in the treatment of obstructive lymphedema.

Dynamic reconstruction of the abdominal wall using a reinnervated free rectus femoris muscle transfer

Dynamic reconstruction of the abdominal wall using a free reinnervated rectus femoris muscle and an island tensor fascia lata transfer was performed for a large herniation with loss of the bilateral rectus abdominis muscles of the abdominal wall. The tensor fascia lata transfer was used to close an inner side of the abdominal defect, and the rectus femoris muscle replaced the rectus abdominis muscle deficit. The motor nerve of the rectus femoris muscle was sutured to the motor branch of the intercostal nerve. Postoperatively, the transferred rectus femoris muscle was reinnervated via electromyography, and there was no abdominal protrusion and no hernia recurrence.

Molecular cloning and characterization of a novel dual specificity phosphatase, MKP-5

A group of dual specificity protein phosphatases negatively regulates members of the mitogen-activated protein kinase (MAPK) superfamily, which consists of three major subfamilies, MAPK/extracellular signal-regulated kinase (ERK), stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), and p38. Nine members of this group of dual specificity phosphatases have previously been cloned. They show distinct substrate specificities for MAPKs, different tissue distribution and subcellular localization, and different modes of inducibility of their expression by extracellular stimuli. Here we have cloned and characterized a novel dual specificity phosphatase, which we have designated MKP-5. MKP-5 is a protein of 482 amino acids with a calculated molecular mass of 52.6 kDa and consists of 150 N-terminal amino acids of unknown function, two Cdc25 homology 2 regions in the middle, and a C-terminal catalytic domain. MKP-5 binds to p38 and SAPK/JNK, but not to MAPK/ERK, and inactivates p38 and SAPK/JNK, but not MAPK/ERK. p38 is a preferred substrate. The subcellular localization of MKP-5 is unique; it is present evenly in both the cytoplasm and the nucleus. MKP-5 mRNA is widely expressed in various tissues and organs, and its expression in cultured cells is elevated by stress stimuli. These results suggest that MKP-5 is a novel type of dual specificity phosphatase specific for p38 and SAPK/JNK.

Structure and function of human prepro-orexin gene

Orexin-A and -B are recently identified potent orexigenic peptides that are derived from the same precursor peptide and are highly specifically localized in neurons located in the lateral hypothalamic area, a region classically implicated in feeding behavior. We cloned the whole length of the human prepro-orexin gene and corresponding cDNA. The human prepro-orexin mRNA was predicted to encode a 131-residue precursor peptide (prepro-orexin). The human prepro-orexin gene consists of two exons and one intron distributed over 1432 base pairs. The 143-base pair first exon includes the 5'-untranslated region and a small part of the coding region that encodes the first seven residues of the secretory signal sequence. The second exon contains the remaining portion of the open reading frame and 3'-untranslated region. The 3.2 kilobase pairs of the 5'-upstream region from a cloned human prepro-orexin gene promoter is sufficient to direct the expression of the Escherichia coli beta-galactosidase (lacZ) gene in transgenic mice to neurons in the lateral hypothalamic area and adjacent regions. The lacZ-positive neurons were positively stained with anti-orexin antibody but not with anti-melanin-concentrating hormone antibody. These findings suggest that this genomic fragment contains all the necessary elements for appropriate expression of the gene and will be useful for the targeted expression of the exogenous gene in orexin-containing neurons. These mice might also be useful for examining the molecular mechanisms by which orexin gene expression is regulated.

Ear helix flap for reconstruction of total loss of the upper eyelid

We present a patient with a recurrent carcinoma of the right upper eyelid who underwent resection of the subtotal upper eyelid resulting in a full-thickness defect. The eyelid was reconstructed with advanced conjunctival lining and an ascending helix chondrocutaneous flap from the right auricle. This flap was nourished with a reverse flow of the frontal branch of the superficial temporal vessels. A superficial temporal vein of the flap was anastomosed to the zygomaticofacial branch of the superficial temporal vein at the lateral canthal region to ensure adequate drainage. The flap survived without any congestion. An ascending helix flap is the best candidate for total loss of the upper eyelid.

[Usefulness of percutaneous sclerosing treatment for low-flow vascular lesions]

Peripheral vascular lesions may occur as a result of various clinical problems, cosmetic or dysfunctional causes, or bleeding. In severe cases, coagulopathy and congestive heart failure may occur. Although the efficacy of transarterial embolization (TAE) for arterial vascular lesions is well known, TAE has no effect on low-flow vascular lesions (venous malformations, venous angiomas, and venous components of arteriovenous malformation). Therefore, in such cases, a percutaneous approach is the best method, and we consider sclerotherapy to be the most useful conservative treatment. The primary objective of this study was to confirm the efficacy of percutaneous sclerosing treatment for peripheral low-flow vascular lesions. Lesions were classified on the basis of state of blood flow and morphologic features, and infiltration was classified on the basis of angiographic features and magnetic resonance imaging (MRI) findings. In sclerosing treatment, we used 5% solutions of polidocanol, absolute ethanol, and N-butyl-2-cyanoacrylate (NBCA) as sclerosing agents. Each type of lesion, static or slow-flow, cystic, or localized, showed remarkable improvement after sclerosing treatment with only polidocanol. However, for moderate-to-fast-flow lesions, another sclerosing agent (absolute ethanol/NBCA) was needed. With diffuse infiltrative lesions, surgical repair might be needed, but we recognize the usefulness of sclerosing treatment for functional or cosmetic improvement in these cases.

One type of chalcone synthase gene expressed during embryogenesis regulates the flavonoid accumulation in citrus cell cultures

To elucidate the relationship between the expression of chalcone synthase (CHS) genes and the production of flavonoid in citrus cell cultures, two cDNA clones encoding CHS were isolated (CitCHS1 and CitCHS2) from the citrus. The accumulation of CitCHS2 mRNA was notably induced by embryogenesis but CitCHS1 mRNA was not. There was no detectable accumulation of flavonoid in the undifferentiated calli, but flavonoid accumulated after the morphological changes to embryoids. These results indicate that two CHS genes differentially expressed during citrus somatic embryogenesis and CitCHS2 may regulate the accumulation of flavonoid in citrus cell cultures.

Denervation of Pacinian corpuscles: electron microscopic observations in the rat following nerve transection

Nerve transection using rat sciatic nerves was employed to observe morphologic changes in the periodic denervation of Pacinian corpuscles. During periods of from 1 to 20 weeks after surgery, a total of 15 corpuscles were obtained under the operating microscope and processed for morphologic analysis using light and electron microscopes. Based on the morphologic findings, normal corpuscles were composed of an axon terminal and inner and outer core cells. Following nerve transection, the axon terminal immediately disappeared at 1 week, but the original inner and outer core cells were preserved, with macrophage migration occurring in the outer core. After 8 weeks, the circular regularity of the inner and outer core lamellae was occasionally broken. The lamellae had wavy courses and there were many empty spaces in the inner core. Even at 20 weeks after denervation, there was interruption in the continuity of the outer core cells; the membranous structure of the outer core and the lamellar structure of the inner core were well-preserved; the outer and inner core cells were still present. Simultaneously, a small number of collagen fibrils were observed between the inner and outer core cells from the earliest postoperative stage. These fibrils increased in number in later stages. The results suggest that, immediately after destruction of axon terminals, macrophages migrate into the interlamellar spaces where they engulf the debris of the degenerated axon terminals. The degeneration of the corpuscles seems to be similar to that of denervated nerve axons; therefore, the inner core cells, which are continuous with the Schwann cells, maintain their original condition for at least 20 weeks after corpuscle denervation. The outer core cells, which are continuous with the perineurial nerve cells, are assumed to be the main cells producing the collagen fibrils in the denervated Pacinian corpuscles.

Neurons containing orexin in the lateral hypothalamic area of the adult rat brain are activated by insulin-induced acute hypoglycemia

Orexin-A and -B (also known as hypocretin-1 and -2) are neuropeptides which stimulate food intake when administered intracerebroventricularly. Orexins are specifically localized in neurons within and around the lateral hypothalamic area (LHA). Previous electrophysiological studies have demonstrated that some neurons in the LHA are activated by hypoglycemia, and are therefore termed 'glucose-sensitive neurons'. In the present study, we examined whether orexin-containing neurons are activated in the hypoglycemic states, using Fos-like immunoreactivity (FLI) as a marker of neuronal activation. We observed that FLI was induced in the LHA by acute insulin treatment. Double staining with anti-Fos and anti-orexin antibodies revealed that up to 33% of the orexin-containing neurons in the LHA also expressed FLI under the hypoglycemic condition. These results suggest that some populations of neurons which contain orexins are activated under hypoglycemic conditions.

Flow-through thin latissimus dorsi perforator flap for repair of soft-tissue defects in the legs

Flow-through thin latissimus dorsi perforator flaps were used in six cases with complicated defects of the legs. This flap has a small amount of latissimus dorsi muscle with a considerable amount of fatty tissue removed to make a thin flap. In addition, the flap has several branches of the subscapular vessel, which are interposed to the recipient vessels of the legs. The advantages of this thin flap are: (1) flow-through vascular reconstruction can preserve the main vessels of the damaged legs; (2) the double arterial inflows and venous drainage systems of the flap ensure safe vascularization of the flap; (3) a flow-through venous drainage system from the distal extremities can also be established to prevent congestion of the affected legs; (4) this flap is versatile (it can be either thin or large); and (5) even in emergent ischemic legs, simultaneous elevation of the flap is possible with preparation of the legs. This flow-through flap is indicated for: (1) cases with a large skin defect and obstruction of the main vessels in the leg; (2) cases with a possibility of tumor recurrence in the legs; and (3) young women or girls with a large defect in the legs, rather than the rectus abdominis musculocutaneous flap.

Free vascularized appendix transfer for reconstruction of penile urethras with severe fibrosis

Despite the development of newer techniques with a free radial forearm tube flaps for phallus reconstruction, severe urethral strictures are still seen in such cases after irradiation or repeated infection because of the paucity of healthy, well-vascularized tissue. For urethral reconstruction in cases with poorly vascularized tissue as well as for total penile creation, a new technique involving a free vascularized appendix transfer combined with a radial forearm osteocutaneous flap was successfully used in two cases. The appendix provides a normal tube structure composed of a muscular tubular layer lined with mucosal epithelium. It has no hair and has rich vascularization. This results in little stricture at the junction with the original urethra, no occurrence of urethral stones, and possible postoperative enlargement of the diameter with changes in catheters. This method will allow a patient with severe fibrosis around the urethra to undergo one-stage phallus reconstruction with minimal complications.

Isolation of Biopterin-alpha-glucoside from Spirulina (Arthrospira) platensis and Its Physiologic Function

: A fluorescent substance was isolated from the cyanobacterium with a yield of 4.5 mg per 10 g of dried Spirulina (Arthrospira) platensis cells by gentle extraction and ethanol fractionation followed by column chromatography. The fluorescent substance, which has absorption maxima at 256 nm and 362 nm (pH 8.4), was identified as biopterin-alpha-glucoside by spectrophotometry and nuclear magnetic resonance spectroscopy. Biopterin-alpha-glucoside prevented decolorization of the photosynthetic pigments, chlorophyll a, phycocyanin, and carotenoids in photosynthetic vesicles of Spirulina platensis cells, by ultraviolet irradiation.

Functional relationship between age-related immunodeficiency and learning deterioration

Disordered immune responses are supposed to alter the function of the central nervous system through the neuroendocrine immunomodulation network. In this paper, we studied the influence of the immune function on learning performances from the angle of pharmacology using aged garlic extract (AGE), an immunomodulator. Splenocyte proliferation, induced by concanavalin A or lipopolysaccharide, and the antibody production response were declined in senescence accelerated mouse-prone 8 (SAMP8) aged 12 months compared with age-matched SAMR1 (SAM-resistant 1). Chronic oral administration of AGE-containing food (2%, w/w) significantly enhanced the immune responses of both SAMP8 and SAMR1. Male ddY mice were thymectomized 4 weeks after birth and fed AGE-containing food after the operation until the experiments were finished. Learning performances, brain monoamine content and choline acetyltransferase (ChAT) activity, as well as the immune response were evaluated 10 months after the operation. Thymectomy resulted in not only immunodeficiency, but also deteriorated learning ability. AGE treatment prevented the reduction of the antibody production response induced by thymectomy and improved the thymectomy-induced deterioration of learning behaviours in passive avoidance performance and in a spatial memory task. The contents of hypothalamic noradrenaline, 3,4-dihydroxyphenylacetic acid and homovanillic acid, and the hypothalamic ChAT activity were increased in thymectomized mice compared to those of sham-operated control, while AGE treatment restored them to the control levels. These results suggest that the improvement of immune function is closely related to the amelioration of age-associated deterioration of learning and memory.

Characterization of a cDNA homologous to carotenoid-associated protein in citrus fruits

A cDNA (CitPAP) homologous to a gene encoding for Cucumis sativus carotenoid-associated protein (CHRC) has been isolated from satsuma mandarin (Citrus unshiu Marc.). Unlike ChrC whose expression was limited only in mature fruits (containing chromoplasts), CitPAP transcripts were detected in all the tissues examined including fruits, flowers and leaves. In this respect, CitPAP was rather close to a gene encoding for pepper plastid-lipid-associated protein (PAP), which exhibits ubiquitous expression in bell pepper organs containing chloroplasts or chromoplasts. CitPAP, however, differed from PAP in the magnitude and pattern of RNA accumulation. These results might indicate a novel function of CitPAP.

Free combined anterolateral thigh flap and vascularized fibula for wide, through-and-through oromandibular defects

Through-and-through oromandibular defects require the greatest amount of soft-tissue volume among the transfers for head and neck defects. A new method, a large anterolateral thigh flap combined with a vascularized fibula graft in a chimera fashion, has been used for two patients with wide through-and-through oromandibular defects. Among the candidates for such a large skin flap, the anterolateral thigh flap seems to be the best, for the following reasons. (1) Its pedicle, the lateral circumflex femoral system, has several major branches of equal size of anastomosis of the peroneal vessels. (2) As the majority of such patients with multiple previous surgery have lost recipient vessels near the mandible, the longest vascular pedicle is required. (3) There is no need for positional changes, and simultaneous flap elevation with the tumor resectioning is possible. (4) Use of the fibula allows for reconstruction of the entire mandible, if necessary. (5) Some of the shortcomings of individual donor sites for massive composite osteocutaneous flaps are minimized, because each component consists of two donor sites. (6) Operating time for this flap elevation is minimized, compared to that for massive composite osteocutaneous flaps, because the individual components can be obtained simultaneously by two teams.

Flow-through vascularized toe-joint transfer for reconstruction of segmental loss of an amputated finger

A segmental finger defect was reconstructed in a 46-year-old woman with a free flow-through vascularized toe-joint, including the proximal interphalangeal joint, the plantar digital nerve, and tendons of the second toe. The advantages of this composite flap are: (1) The segmental loss of the finger can be easily reconstructed to achieve a normal anatomic structure. (2) Excellent cosmesis is achieved, compared with conventional flaps such as the groin flap. (3) The distal segment of the donor toe can be preserved. (4) The transected digital arteries of the amputated finger can be simultaneously reconstructed with a flow-through arterial interposition. (5) The digital nerve can be repaired with a vascularized plantar digital nerve graft.

Differential roles of ERK and p38 MAP kinase pathways in positive and negative selection of T lymphocytes

Clonal selection of T lymphocytes is essential for establishing self/non-self discrimination of immune recognition. It is known that cell surface signals such as avidity and valency of TCR-ligand interactions influence the fate of individual thymocytes, founding a primary repertoire of T cells. However, intracellular signals that govern positive and negative selection in the thymus have been unclear. The present study using the retroviral gene transfer technique shows that MKK1 activation in developing T cells is sufficient for providing positive selection signals. We also show that the MKK6-p38 signaling pathway is critically involved in inducing negative selection of thymocytes. These results suggest that intracellular signals through different MAP kinase cascades selectively guide positive and negative selection of T lymphocytes.

Paraumbilical perforator flap without deep inferior epigastric vessels

With the introduction of supramicrosurgery, a new paraumbilical perforator flap without a deep inferior epigastric vessel and with very small perforator anastomoses was used for nine patients. The abdominal defects of two patients, the lower leg or foot defects of five patients, and the scalp defects of two patients were repaired with an island perforator flap. The advantages of the paraumbilical perforator flap are as follows: (1) there is a very short operating time for flap elevation; (2) there is no invasion or sacrifice of any rectus abdominis muscle; (3) for middle-aged, obese patients, the donor site may be the best from the cosmetic point of view; (4) many small recipient vessels to anastomose the perforator exist throughout the body; (5) a thin skin flap with adequate thickness can be created easily with simultaneous removal of fatty tissue; (6) secondary defatting around the perforator can be done by minor surgery under local anesthesia; and (7) a vascularized adiposal flap with adequate thickness can be created easily. This flap seems to be indicated for female patients with defects in the abdominal wall and the lower leg. The island flap can easily resurface abdominal skin defects, such as intestinal fistula or radiation ulcers. The free flap is suitable for covering defects in the lower leg, foot, and scalp temporarily before administration of a tissue expander.

[Efficacy and safety of two methods of administration of granisetron injection for nausea and vomiting induced by chemotherapy for tumors in hematopoietic organs--a randomized crossover comparison between intravenous drip infusion and intravenous bolus injection]

We investigated the efficacy and safety of two methods of granisetron injection to treat nausea and vomiting induced by chemotherapy for tumors in hematopoietic organs. The methods of administration were intravenous drip infusion over 30 minutes, which is the conventional method, and intravenous bolus injection. In this study, 89.5% of patients in both groups (17/19 for each) were free from vomiting. No serious adverse events were observed in either administration group. Abnormal laboratory test values suspected to be related to granisetron were observed in 3 cases in the bolus injection group and in 2 cases in the drip infusion group. but did not pose any clinical problem. These results demonstrated the safety of both methods of administration. In conclusion, it is considered that granisetron intravenous bolus injection can be considered as the method of choice for the prevention of nausea and vomiting induced by chemotherapy for tumors in hematopoietic organs.

Nuclear export of cyclin B1 and its possible role in the DNA damage-induced G2 checkpoint

M-phase-promoting factor (MPF), a complex of cdc2 and a B-type cyclin, is a key regulator of the G2/M cell cycle transition. Cyclin B1 accumulates in the cytoplasm through S and G2 phases and translocates to the nucleus during prophase. We show here that cytoplasmic localization of cyclin B1 during interphase is directed by its nuclear export signal (NES)-dependent transport mechanism. Treatment of HeLa cells with leptomycin B (LMB), a specific inhibitor of the NES-dependent transport, resulted in nuclear accumulation of cyclin B1 in G2 phase. Disruption of an NES which has been identified in cyclin B1 here abolished the nuclear export of this protein, and consequently the NES-disrupted cyclin B1 when expressed in cells accumulated in the nucleus. Moreover, we show that expression of the NES-disrupted cyclin B1 or LMB treatment of the cells is able to override the DNA damage-induced G2 checkpoint when combined with caffeine treatment. These results suggest a role of nuclear exclusion of cyclin B1 in the DNA damage-induced G2 checkpoint.

T lymphocyte activation signals for interleukin-2 production involve activation of MKK6-p38 and MKK7-SAPK/JNK signaling pathways sensitive to cyclosporin A

p38/CSBP, a subgroup member of mitogen-activated protein kinase (MAPK) superfamily molecules, is known to be activated by proinflammatory cytokines and environmental stresses. We report here that p38 is specifically activated by signals that lead to interleukin-2 (IL-2) production in T lymphocytes. A p38 activator MKK6 was also markedly activated by the same stimulation. Pretreatment of cells with SB203580, a specific inhibitor of p38, as well as expression of a dominant-negative mutant of MKK6, suppressed the transcriptional activation of the IL-2 promoter. We also demonstrated that MKK7, a recently described MAPK kinase family member, plays a major role in the activation of stress-activated protein kinase (SAPK)/c-Jun NH2-terminal kinase (JNK) in T lymphocytes. Moreover, a dominant-negative mutant of MKK7 abrogated the transcriptional activation of the distal nuclear factor of activated T cells response element in the IL-2 promoter. Cyclosporin A, a potent immunosuppressant, inhibited activation of both p38 and SAPK/JNK pathways but not the MAPK/extracellular signal-regulated kinase (ERK) pathway. Our results indicate that both MKK6 to p38 and MKK7 to SAPK/JNK signaling pathways are activated in a cyclosporin A-sensitive manner and contribute to IL-2 gene expression in T lymphocytes.

Characterization of gene repertoires at mature stage of citrus fruits through random sequencing and analysis of redundant metallothionein-like genes expressed during fruit development

We carried out a random sequencing of cDNA library derived from mature citrus fruit (Citrus unshiu Marc.) for identifying the gene repertoires expressed at the mature stage. Among 297 clones analyzed, 195 cDNA clones (65.7%) were putatively identified to previously characterized genes with optimized (OPT) scores of >/=200 through a homology search to DNA database, whereas 102 clones (34.3%) resulted in low OPT scores (<200) and did not show any significant sequence identity with previously published genes. Among them, clones homologous to metallothionein (MT)-like genes appeared 62 times, being mostly redundant, and accounting for about 20.9% of the total 297 clones. To gain a better understanding of the MT-like genes, two types of cDNA clones were isolated. One clone (CitMT36) resembled the type 2 MT gene containing Cys-X-Cys motifs in both N- and C-terminal, but the consensus sequence in the N-terminal domain, Cys-Cys and Cys-X-X-Cys was modified in CitMT36 to X-Cys and Cys-X-X-X, respectively. We suggest that these form a 'novel type 2' group of MT-like clones. The other clone (CitMT45) showed homology to type 3 MT-like genes, which have been found in mostly fruit tissues so far. By Southern blot analysis, both clones showed one or two bands, suggesting that both CitMT36 and CitMT45 are present in single or a few copies in the citrus genome. Transcripts of CitMT36 were evenly detected in all tissues examined, whereas those of CitMT45 were detected primarily in fruit during the developmental phase. Neither of the MT-like genes was induced in leaves by Zn and Cu. Collectively, MT-like genes from citrus would be regulated differentially depending on the fruit developmental stage and organs, indicating a change in their expression under the different physiological and molecular environment of fruit cells.