RESUMO
A highly polymethylated flavone that effectively inhibited cytochrome P450s (CYPs) 1A2 and 3A4 (IC(50) = 2.41 and 1.71 µM) in vitro was isolated from thyme leaves (Thymus saturoides) purchased from a Japanese market. Its structure was spectroscopically identified as 4',5-dihydroxy-3',6,7,8-tetramethoxy flavone (8-methoxycirsilineol, 1). This is the first report describing a strong inhibitor of CYP1A2 and 3A4 isolated from Thymus saturoides.
Assuntos
Inibidores do Citocromo P-450 CYP1A2 , Inibidores do Citocromo P-450 CYP3A , Inibidores Enzimáticos/química , Flavonas/química , Thymus (Planta)/química , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/farmacologia , Flavonas/isolamento & purificação , Flavonas/farmacologia , Humanos , Folhas de Planta/químicaRESUMO
MAM domain containing glycosilphosphatidilinositol anchor 1 (MDGA1) is an IgCAM protein present in many vertebrate species including humans. In mammals, MDGA1 is expressed by a subset of neurons in the developing brain and thought to function in neural cell migration. We identified a fish ortholog of mdga1 by a gene-trap screen utilizing the Frog Prince transposon in medaka (Japanese killifish, Oryzias latipes). The gene-trap vector was inserted into an intronic region of mdga1 to form a chimeric protein with green fluorescent protein, allowing us to monitor mdga1 expression in vivo. Expression of medaka mdga1 was seen in various types of embryonic brain neurons, and specifically in neurons migrating toward their target sites, supporting the proposed function of MDGA1. We also isolated the closely related mdga2 gene, whose expression partially overlapped with that of mdga1. Despite the fact that the gene-trap event eliminated most of the functional domains of the Mdga1 protein, homozygous embryos developed normally without any morphological abnormality, suggesting a functional redundancy of Mdga1 with other related proteins. High sequential homology of MDGA proteins between medaka and other vertebrate species suggests an essential role of the MDGA gene family in brain development among the vertebrate phylum.
Assuntos
Glicosilfosfatidilinositóis/genética , Oryzias/genética , Animais , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Clonagem Molecular , Elementos de DNA Transponíveis , Fluorescência , Regulação da Expressão Gênica no Desenvolvimento , Mutação , Oryzias/embriologiaRESUMO
There are approximately 69 genes encoding aspartyl protease homologues in Arabidopsis thaliana, and most of the gene products constitute a novel subfamily of aspartic proteases. However, their physiological roles are largely unknown. As an initial step to shed light on the roles of these nepenthesin-like aspartic proteases (NAPs), a phylogenetic tree was constructed, which indicated that these proteases are classified into several distinct sub-sub-groups. Based on these results, specific primers were designed for genes selected from several of these groups and their tissue expression was investigated using RT-PCR. The results indicated that these genes are widely expressed in several tissues, such as leaves, stems, seeds and pods, suggesting ubiquitous occurrence and multiple functions of the corresponding proteases in the tissues of A. thaliana.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Ácido Aspártico Endopeptidases/genética , Perfilação da Expressão Gênica , Arabidopsis/enzimologia , Proteínas de Arabidopsis/classificação , Ácido Aspártico Endopeptidases/classificação , Eletroforese em Gel de Ágar , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Transcrição GênicaRESUMO
The medaka fish (Oryzias latipes) is an emerging model organism for which a variety of unique developmental mutants have now been generated. Our recent mutagenesis screening of the medaka identified headfish (hdf), a null mutant for fgf receptor 1 (fgfr1), which fails to develop structures in the trunk and tail. Despite its crucial role in early development, the functions of Fgfr1-mediated signaling have not yet been well characterized due to the complexity of the underlying ligand-receptor interactions. In our present study, we further elucidate the roles of this pathway in the medaka using the hdf (fgfr1) mutant. Because Fgfr1 is maternally supplied in fish, we first generated maternal-zygotic (MZ) mutants by transplanting homozygous hdf germ cells into sterile interspecific hybrids. Interestingly, the host hybrid fish recovered their fertility and produced donor-derived mutant progeny. The resulting MZ mutants also exhibited severe defects in their anterior head structures that are never observed in the corresponding zygotic mutants. A series of detailed analyses subsequently revealed that Fgfr1 is required for the anterior migration of the axial mesoderm, particularly the prechordal plate, in a cell-autonomous manner, but is not required for convergence movement of the lateral mesoderm. Furthermore, fgfr1 was found to be dispensable for initial mesoderm induction. The MZ hdf medaka mutant was thus found to be a valuable model system to analyze the precise role of fgfr1-mediated signaling in vertebrate early development.