Flowering and Endogenous Levels of Plant Hormones in Lemna Species

The occurrence and endogenous level of various plant hormoneswere measured for the short-day plants Lemna paucicostata 151and 381 and the long-day plant Lemna gibba G3 to determine whetherany of them are involved in the photoperiodic control of flowering.ABA, IAA, GA₁, GA₂₉, GA₃₄, GA₅₃, trans- and cis-zeatin, trans-and cis-ribosyl zeatin, N⁶-(²-isopentenyl) adenine and N⁶-(²-isopentenyl)adenosine were definitely detected in each species, while GA₄was only detected in L. gibba G3 and GA₂₀ was only detectedin L. paucicostata 151. The endogenous levels of ABA and IAAwere in the range of 1–7 ng/g fr wt and were not significantlydifferent in vegetative and flowering plants. The endogenousgibberellin levels were generally higher in Lemna grown underlong-day rather than short-day conditions. The endogenous cytokininlevels were almost the same in both flowering and vegetativeplants of L. paucicostata 151 and 381. In L. gibba G3, however,the level of cis-ribosyl zeatin, N⁶-(²-isopentenyl) adenineand N⁶-(²-sopentenyl) adenosine were higher in vegetative thanin flowering plants. These results indicate that there is not necessarily a directrelation between endogenous plant hormone levels and flowering,and that the chemical basis for the photoperiodic control offlowering cannot be explained solely by changes in hormone levels.The possibility remains, however, that one or more of the planthormones has some influence of secondary importance on the floweringprocess in Lemna. (Received January 29, 1986; Accepted July 12, 1986)     

Analyses of beta-1 syntrophin, syndecan 2 and gem GTPase as candidates for chicken muscular dystrophy.

Despite intensive studies of muscular dystrophy of chicken, the responsible gene has not yet been identified. Our recent studies mapped the genetic locus for abnormal muscle (AM) of chicken with muscular dystrophy to chromosome 2q using the Kobe University (KU) resource family, and revealed the chromosome region where the AM gene is located has conserved synteny to human chromosome 8q11-24.3, where the beta-1 syntrophin (SNTB1), syndecan 2 (SDC2) and Gem GTPase (GEM) genes are located. It is reasonable to assume those genes might be candidates for the AM gene. In this study, we cloned and sequenced the chicken SNTB1, SDC2 and GEM genes, and identified sequence polymorphisms between parents of the resource family. The polymorphisms were genotyped to place these genes on the chicken linkage map. The AM gene of chromosome 2q was mapped 130 cM from the distal end, and closely linked to calbindin 1 (CALB1). SNTB1 and SDC2 genes were mapped 88.5 cM distal and 27.6 cM distal from the AM gene, while the GEM gene was mapped 18.5 cM distal from the AM gene and 9.1 cM proximal from SDC2. Orthologues of SNTB1, SDC2 and GEM were syntenic to human chromosome 8q. SNTB1, SDC2 and GEM did not correspond to the AM gene locus, suggesting it is unlikely they are related to chicken muscular dystrophy. However, this result also suggests that the genes located in the proximal region of the CALB1 gene on human chromosome 8q are possible candidates for this disease.     

Induction of Flowering in Lemna paucicostata by Dicoumarol and 4-Hydroxycoumarin

Dicoumarol, an antagonist of vitamin K, not only promoted theflower-inducing activity of vitamin K₅, but also induced floweringin Lemna paucicostata when added alone to the medium. The flower-inducingactivity of dicoumarol was comparable to that of benzoic acidand could be greatly intensified by simultaneous applicationof benzyladenine as was the case with benzoic acid. Warfarin,another antagonist of vitamin K, did not induce flowering. 4-Hydroxycoumarin, a component of dicoumarol, was also active,but coumarin and 7-hydroxycoumarin were not. Dicoumarol hadonly a slight flower-inducing activity for strains 441 and 6746under continuous light, but had a strong flower-promoting effectunder a near critical photoperiod. That is, the effect of dicoumarolwas daylength-dependent. (Received April 22, 1985; Accepted August 21, 1985)     

Dietary GABA induces endogenous synthesis of a novel imidazole peptide homocarnosine in mouse skeletal muscles

Amino Acids - Carnosine (β-alanyl-l-histidine) is an imidazole dipeptide present at high concentrations in skeletal muscles, where it plays a beneficial role. However, oral intake of carnosine...     

Protocadherin-1 is expressed in the notochord of mouse embryo but is dispensable for its formation

Notochord is an embryonic midline structure that serves as mechanical support for axis elongation and the signaling center for the surrounding tissues. Precursors of notochord are initially induced in the dorsal most mesoderm region in gastrulating embryo and separate from the surrounding mesoderm/endoderm tissue to form an elongated rod-like structure, suggesting that cell adhesion molecules may play an important role in this step. In Xenopus embryo, axial protocadherin (AXPC), an orthologue of mammalian Protocadherin-1 (PCDH1), is indispensable for the assembly and separation from the surrounding tissue of the notochord cells. However, the role of PCDH1 in mammalian notochord remains unknown. We herein report that PCDH1 is expressed in the notochord of mouse embryo and that PCDH1-deficient mice form notochord normally. First, we examined the temporal expression pattern of pcdh1 and found that pcdh1 mRNA was expressed from embryonic day (E) 7.5, prior to the stage when notochord cells detach from the surrounding endoderm tissue. Second, we found that PCDH1 protein is expressed in the notochord of mouse embryos in addition to the previously reported expression in endothelial cells. To further investigate the role of PCDH1 in embryonic development, we generated PCDH1-deficient mice using the CRISPR-Cas9 system. In PCDH1-deficient embryos, notochord formation and separation from the surrounding tissue were normal. Structure and marker gene expression of notochord were also unaffected by loss of PCDH1. Major vascular patterns in PCDH1-deficient embryo were essentially normal. These results suggest that PCDH1 is dispensable for notochord formation, including the tissue separation process, in mammalian embryos. We successfully identified the evolutionary conserved expression of PCDH1 in notochord, but its function may differ among species.     

Induction of GPR40 positively regulates cell motile and growth activities in breast cancer MCF-7 cells

Abstract

Free fatty acid (FFA) receptors belong to a member of G-protein-coupled receptors. GPCR 120 (GPR120) and GPR40 are identified as FFA receptors and activated via the binding of long- and medium-chain FFAs. The aim of this study was to assess the effects of GPR120 and GPR40 on cell motility and growth in breast cancer cells treated with tamoxifen (TAM). MCF-7 cells were continuously treated with TAM for approximately 6?months. The expression level of GPR40 gene was markedly higher in the long-term TAM treated (MCF-TAM) cells than in MCF-7 cells. In cell motility assay, MCF-TAM cells indicated the high cell motile activity, compared with MCF-7 cells. The cell motile activity of MCF-TAM cells was suppressed by a selective GPR40 antagonist, GW1100. To evaluate the effects of GPR40 on cell growth activity under estrogen-free conditions, cells were maintained in serum-free DMEM without phenol red for 2?days. In estrogen-free conditioned medium, the cell growth rate of MCF-TAM cells was significantly higher than that of MCF-7 cells. In addition, treatment of GW1100 reduced the cell growth rate of MCF-TAM cells. These results suggest that the cell motile and growth activities may be positively regulated through the induction of GPR40 by the long-term TAM treatment in MCF-7 cells.     

GPAT2, a mitochondrial outer membrane protein,in piRNA biogenesis in germline stem cells

piRNA (PIWI-interacting RNA) is a germ cell–specific small RNA in which biogenesis PIWI (P-element wimpy testis) family proteins play crucial roles. MILI (mouse Piwi-like), one of the three mouse PIWI family members, is indispensable for piRNA production, DNA methylation of retrotransposons presumably through the piRNA, and spermatogenesis. The biogenesis of piRNA has been divided into primary and secondary processing pathways; in both of these MILI is involved in mice. To analyze the molecular function of MILI in piRNA biogenesis, we utilized germline stem (GS) cells, which are derived from testicular stem cells and possess a spermatogonial phenotype. We established MILI-null GS cell lines and their revertant, MILI-rescued GS cells, by introducing the Mili gene with Sendai virus vector. Comparison of wild-type, MILI-null, and MILI-rescued GS cells revealed that GS cells were quite useful for analyzing the molecular mechanisms of piRNA production, especially the primary processing pathway. We found that glycerol-3-phosphate acyltransferase 2 (GPAT2), a mitochondrial outer membrane protein for lysophosphatidic acid, bound to MILI using the cells and that gene knockdown of GPAT2 brought about impaired piRNA production in GS cells. GPAT2 is not only one of the MILI bound proteins but also a protein essential for primary piRNA biogenesis.     

Matrix-Embedded Osteocytes Regulate Mobilization of Hematopoietic Stem/Progenitor Cells

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Functional Analysis of Deep Intronic SNP rs13438494 in Intron 24 of PCLO Gene

The single nucleotide polymorphism (SNP) rs13438494 in intron 24 of PCLO was significantly associated with bipolar disorder in a meta-analysis of genome-wide association studies. In this study, we performed functional minigene analysis and bioinformatics prediction of splicing regulatory sequences to characterize the deep intronic SNP rs13438494. We constructed minigenes with A and C alleles containing exon 24, intron 24, and exon 25 of PCLO to assess the genetic effect of rs13438494 on splicing. We found that the C allele of rs13438494 reduces the splicing efficiency of the PCLO minigene. In addition, prediction analysis of enhancer/silencer motifs using the Human Splice Finder web tool indicated that rs13438494 induces the abrogation or creation of such binding sites. Our results indicate that rs13438494 alters splicing efficiency by creating or disrupting a splicing motif, which functions by binding of splicing regulatory proteins, and may ultimately result in bipolar disorder in affected people.     

Direct Induction of Chondrogenic Cells from Human Dermal Fibroblast Culture by Defined Factors

The repair of large cartilage defects with hyaline cartilage continues to be a challenging clinical issue. We recently reported that the forced expression of two reprogramming factors (c-Myc and Klf4) and one chondrogenic factor (SOX9) can induce chondrogenic cells from mouse dermal fibroblast culture without going through a pluripotent state. We here generated induced chondrogenic (iChon) cells from human dermal fibroblast (HDF) culture with the same factors. We developed a chondrocyte-specific COL11A2 promoter/enhancer lentiviral reporter vector to select iChon cells. The human iChon cells expressed marker genes for chondrocytes but not fibroblasts, and were derived from non-chondrogenic COL11A2-negative cells. The human iChon cells formed cartilage but not tumors in nude mice. This approach could lead to the preparation of cartilage directly from skin in human, without going through pluripotent stem cells.