共查询到20条相似文献,搜索用时 15 毫秒
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Neural crest development is regulated by the transcription factor Sox9 总被引:14,自引:0,他引:14
The neural crest is a transient migratory population of stem cells derived from the dorsal neural folds at the border between neural and non-neural ectoderm. Following induction, prospective neural crest cells are segregated within the neuroepithelium and then delaminate from the neural tube and migrate into the periphery, where they generate multiple differentiated cell types. The intrinsic determinants that direct this process are not well defined. Group E Sox genes (Sox8, Sox9 and Sox10) are expressed in the prospective neural crest and Sox9 expression precedes expression of premigratory neural crest markers. Here, we show that group E Sox genes act at two distinct steps in neural crest differentiation. Forced expression of Sox9 promotes neural-crest-like properties in neural tube progenitors at the expense of central nervous system neuronal differentiation. Subsequently, in migratory neural crest cells, SoxE gene expression biases cells towards glial cell and melanocyte fate, and away from neuronal lineages. Although SoxE genes are sufficient to initiate neural crest development they do not efficiently induce the delamination of ectopic neural crest cells from the neural tube consistent with the idea that this event is independently controlled. Together, these data identify a role for group E Sox genes in the initiation of neural crest development and later SoxE genes influence the differentiation pathway adopted by migrating neural crest cells. 相似文献
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We describe the identification and detailed expression pattern of a second Drosophila Sox gene, SoxNeuro (SoxN), highly related to mammalian group B Sox1, 2, 3 genes. SoxN is expressed in a highly dynamic pattern during embyogenesis, being associated with the development of the central nervous system (CNS), from the early steps onwards. We present strong evidence that the early SoxN neuroectoderm expression is controlled by the zygotic dorso-ventral patterning genes (dpp, sog, brk, twi). 相似文献
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Extensive studies in vertebrate cells have assigned a central role to Rel/NF-kappa B and AP-1 family members in the control of apoptosis. We ask here whether parallel pathways might function in Drosophila by determining if Rel/NF-kappa B or AP-1 family members contribute to the steroid-triggered death of larval salivary glands during Drosophila metamorphosis. We show that two of the three Drosophila Rel/NF-kappa B genes are expressed in doomed salivary glands and that one family member, Dif, is induced in a stage-specific manner immediately before the onset of programmed cell death. Similarly, Djun is expressed for many hours before salivary gland cell death while Dfos is induced in a stage-specific manner, immediately before this tissue is destroyed. We show that null mutations in the three Drosophila Rel/NF-kappa B family members, either alone or in combination, have no apparent effect on this death response. In contrast, Dfos is required for the proper timing of larval salivary gland cell death as well as the proper induction of key death genes. This study demonstrates a role for AP-1 in the stage-specific steroid-triggered programmed cell death of larval tissues during Drosophila metamorphosis. 相似文献
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Two novel annexins from Drosophila melanogaster. Cloning, characterization, and differential expression in development 总被引:4,自引:0,他引:4
P A Johnston M S Perin G A Reynolds S A Wasserman T C Südhof 《The Journal of biological chemistry》1990,265(19):11382-11388
The annexins are a family of homologous Ca2(+)- and phospholipid-binding proteins that until now have only been found in vertebrates. cDNA clones encoding two novel annexins from Drosophila melanogaster were isolated and characterized. RNA blots indicate that the messages for the two Drosophila proteins are differentially expressed in development, with one message being expressed throughout development, while the other is only found in early embryos and adult flies. In situ hybridizations localize the two Drosophila genes to 93B and 19A-4,7. A similarly high degree of homology relates Drosophila annexins to different vertebrate annexins, indicating that the Drosophila annexins are not the invertebrate homologues of particular mammalian annexins but that they constitute novel members of the annexin gene family. In continuation with a recently established terminology, the Drosophila annexins will be named annexins IX and X. The biochemical properties of Drosophila annexin X were investigated using recombinant protein. Similar to vertebrate annexins, annexin X bound to liver membranes and liposomes containing phosphatidylserine in a calcium-dependent manner but not to liposomes containing phosphatidylcholine. In addition, annexin X partitioned into the detergent phase of Triton X-114 as a function of calcium. The conservation of the annexin family of Ca2(+)-binding proteins in invertebrates suggests that they have a basic function in cells which is not peculiar to vertebrate biology, and the availability of the Drosophila sequences will open avenues for mutational studies of these functions. 相似文献
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Group B Sox-domain proteins encompass a class of conserved DNA-binding proteins expressed from the earliest stages of metazoan CNS development. In all higher organisms studied to date, related Group B Sox proteins are co-expressed in the developing CNS; in vertebrates there are three (Sox1, Sox2 and Sox3) and in Drosophila there are two (SoxNeuro and Dichaete). It has been suggested there may be a degree of functional redundancy in Sox function during CNS development. We describe the CNS phenotype of a null mutation in the Drosophila SoxNeuro gene and provide the first direct evidence for both redundant and differential Sox function during CNS development in DROSOPHILA: In the lateral neuroectoderm, where SoxNeuro is uniquely expressed, SoxNeuro mutants show a loss or reduction of achaete expression as well as a loss of many correctly specified lateral neuroblasts. By contrast, in the medial neuroectoderm, where the expression of SoxNeuro and Dichaete overlaps, the phenotypes of both single mutants are mild. In accordance with an at least partially redundant function in that region, SoxNeuro/Dichaete double mutant embryos show a severe neural hypoplasia throughout the central nervous system, as well as a dramatic loss of achaete expressing proneural clusters and medially derived neuroblasts. However, the finding that Dichaete and SoxN exhibit opposite effects on achaete expression within the intermediate neuroectoderm demonstrates that each protein also has region-specific unique functions during early CNS development in the Drosophila embryo. 相似文献
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SoxB1基因家族编码一类含有HMG DNA结合结构域的转录因子。目前,已经鉴定出的SoxB1家族成员包括脊椎动物中共有的Sox1a/b、Sox2、Sox3以及硬骨鱼类中特有的Sox19a/19b,它们在性别决定、神经元特化、"干"性细胞自我更新及全能性维持、胚层发育等过程中发挥重要作用。向小鼠成纤维细胞中导入四个关键因子Sox2、Oct4、c-Myc及Klf4,可以成功地将体细胞诱导成具有分化全能性的干细胞,证明了SoxB1因子在发育过程中不可或缺的重要性,也极大地推动了关于SoxB1家族基因的研究。该文将围绕SoxB1基因的最新研究进展作一综述。 相似文献
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Impact of transcription factor Sox8 on oligodendrocyte specification in the mouse embryonic spinal cord 总被引:4,自引:0,他引:4
The myelin-forming oligodendrocytes of the mouse embryonic spinal cord express the three group E Sox proteins Sox8, Sox9, and Sox10. They require Sox9 for their specification from neuroepithelial cells of the ventricular zone and Sox10 for their terminal differentiation and myelination. Here, we show that during oligodendrocyte development, Sox8 is expressed after Sox9, but before Sox10. Loss of Sox8 did not impair oligodendrocyte specification by itself, but enhanced the Sox9-dependent defect. Oligodendrocyte progenitors were still generated in the Sox9-deficient spinal cord, albeit at 20-fold lower rates than in the wildtype. Combined loss of Sox8 and Sox9, in contrast, led to a near complete loss of oligodendrocytes. Other cell types such as ventricular zone cells and radial glia remained unaffected in their numbers as well as their rates of proliferation and apoptosis. Oligodendrocyte development thus relies on the differential contribution of all three group E Sox proteins at various phases. 相似文献
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Hotta K Takahashi H Asakura T Saitoh B Takatori N Satou Y Satoh N 《Developmental biology》2000,224(1):69-80
The notochord has two major roles during chordate embryogenesis, as a source of inductive signals for the patterning of neural tube and paraxial mesoderm and as a supportive organ of the larval tail. Despite the recent identification of mutations that affect the notochord development in vertebrate embryos, little is known about genes that are expressed in the differentiating notochord itself. In the urochordate ascidian Ciona intestinalis, Brachyury (Ci-Bra) plays a key role in notochord differentiation. In a previous study, we isolated cDNA clones for nearly 40 potential Ci-Bra target genes that are expressed in notochord cells (H. Takahashi et al., 1999, Genes Dev. 13, 1519-1523). Here we characterized 20 of them by determining the complete nucleotide sequences of the cDNAs. These genes encode a broad spectrum of divergent proteins associated with notochord formation and function. Two genes encode ascidian homologs of the Drosophila Prickle LIM domain proteins and another encodes the ERM protein, all 3 of which appear to be involved in the control of cytoskeletal architecture. In addition, genes for netrin, leprecan, cdc45, ATP:citrate lyase, ATP sulfurylase/APS kinase, protein tyrosine phosphatase, beta4-galactosyltransferase, fibrinogen-like protein, divergent tropomyosin-like proteins, and Drosophila Pellino-like protein were identified. The observation of the netrin gene expression in the notochord may provide the first molecular evidence that the ascidian notochord is a source of signals as in vertebrates. In addition, the present information should be used to identify nonchordate deuterostome tissues homologous to the notochord as well as genes which are expressed in the notochord cells of vertebrate embryos. 相似文献
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