Expression of a Gene for Major Mitochondrial Protein, ADP/ATP Translocase, during Embryogenesis in the Ascidian <i>Halocynthia roretzi</i>

Miya, Takahito; Makabe, Kazuhiro W.; Satoh, Noriyuki

doi:10.1111/j.1440-169x.1994.00039.x

Cited by 32 publications

(23 citation statements)

References 30 publications

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“…Whole-mount in-situ hybridization was performed as described by Miya et al (Miya et al, 1994;Miya et al, 1997). Specimens were hybridized with digoxigenin (DIG)-labeled macho-1, Hr-PEM1 (Nishida and Sawada, 2001), Hr-POPK-1 (Sasakura et al, 1998b), Hr-ZF1 (Sasakura et al, 2000), Hr-Wnt-5 (Sasakura et al, 1998a) and Hr-PEN1 (Nakamura et al, 2003) antisense RNA probes.…”

Section: Microinjection Of Mos and Synthetic Mrnamentioning

confidence: 99%

POPK-1/Sad-1 kinase is required for the proper translocation of maternal mRNAs and putative germ plasm at the posterior pole of the ascidian embryo

2005

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Maternal mRNAs localized to specific regions in eggs play important roles in the establishment of embryonic axes and germ layers in various species. Type I postplasmic/PEM mRNAs, which are localized to the posterior-vegetal cortex (PVC) of fertilized ascidian eggs, such as the muscle determinant macho-1 mRNA, play key roles in embryonic development. In the present study, we analyzed the function of the postplasmic/PEMRNA Hr-POPK-1, which encodes a kinase of Halocynthia roretzi. When the function of POPK-1 was suppressed by morpholino antisense oligonucleotides, the resulting malformed larvae did not form muscle or mesenchyme, as in macho-1-deficient embryos. Epistatic analysis indicated that POPK-1 acts upstream of macho-1. When POPK-1was knocked down, localization of every Type I postplasmic/PEM mRNA examined, including macho-1, was perturbed, showing diffuse early distribution and eventual concentration into a smaller area. This is the probable reason for the macho-1 dysfunction. The postplasmic/PEMmRNAs such as macho-1 and Hr-PEM1 are co-localized with the cortical endoplasmic reticulum (cER) and move with it after fertilization. Eventually they become highly concentrated into a subcellular structure, the centrosome-attracting body (CAB), at the posterior pole of the cleaving embryos. The suppression of POPK-1 function reduced the size of the domain of concentrated cER at the posterior pole, indicating that POPK-1 is involved in the movement of postplasmic/PEM RNAs via relocalization of cER. The CAB also shrank. These results suggest that Hr-POPK-1 plays roles in concentration and positioning of the cER, as well as in the concentration of CAB materials, such as putative germ plasm, in the posterior blastomeres.

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Section: Microinjection Of Mos and Synthetic Mrnamentioning

confidence: 99%

POPK-1/Sad-1 kinase is required for the proper translocation of maternal mRNAs and putative germ plasm at the posterior pole of the ascidian embryo

2005

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“…Arginyl-tRNA synthetase was used as a probe for ubiquitously distributed maternal mRNA (GenBank accession number, AV383566). Detection of mRNA in whole-mount specimens was carried out essentially as described previously (Miya et al, 1994).…”

Section: In Situ Hybridizationmentioning

confidence: 99%

Maternal mRNAs ofPEMandmacho 1, the ascidian muscle determinant, associate and move with a rough endoplasmic reticulum network in the egg cortex

et al. 2003

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Localization of maternal mRNAs in the egg cortex is an essential feature of polarity in embryos of Drosophila, Xenopus and ascidians. In ascidians, maternal mRNAs such as macho 1, a determinant of primary muscle-cell fate, belong to a class of postplasmic RNAs that are located along the animal-vegetal gradient in the egg cortex. Between fertilization and cleavage, these postplasmic RNAs relocate in two main phases. They further concentrate and segregate in small posterior blastomeres into a cortical structure, the centrosome-attracting body (CAB), which is responsible for unequal cleavages. By using high-resolution, fluorescent, in situ hybridization in eggs,zygotes and embryos of Halocynthia roretzi, we showed that macho 1 and HrPEM are localized on a reticulated structure situated within 2 μm of the surface of the unfertilized egg, and within 8 μm of the surface the vegetal region and then posterior region of the zygote. By isolating cortices from eggs and zygotes we demonstrated that this reticulated structure is a network of cortical rough endoplasmic reticulum (cER) that is tethered to the plasma membrane. The postplasmic RNAs macho 1 and HrPEM were located on the cER network and could be detached from it. We also show that macho 1 and HrPEM accumulated in the CAB and the cER network. We propose that these postplasmic RNAs relocalized after fertilization by following the microfilament- and microtubule-driven translocations of the cER network to the poles of the zygote. We also suggest that the RNAs segregate and concentrate in posterior blastomeres through compaction of the cER to form the CAB. A multimedia BioClip `Polarity inside the egg cortex' tells the story and can be downloaded at www.bioclips.com/bioclip.html

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“…Whole-mount specimens were hybridized in situ at 42°C using digoxigenin-labeled antisense probes, as described by Miya et al (1994). In the experiments indicated, the embryos were dehydrated and rendered transparent with a 1:2 mixture (v/v) of benzyl alcohol and benzyl benzoate after visualization of the hybridization.…”

Section: Whole-mount In Situ Hybridization and Histochemical Stainingmentioning

confidence: 99%

Ascidian Wnt‐5 gene is involved in the morphogenetic movement of notochord cells

Sasakura¹,

Makabe²

2001

Dev Growth Differ

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Wnt proteins play important roles in many developmental events. Wnts are divided into two groups according to biological function. The Wnt-5a class proteins function in morphogenetic movement during embryogenesis. Previously, a Wnt-5 homolog has been isolated from the ascidian, Halocynthia roretzi. HrWnt-5 is expressed in the notochord until the tail-bud stage, implying a role in the notochord. In this study, the function of HrWnt-5 was investigated. When HrWnt-5 mRNA was injected into fertilized eggs, the embryos showed morphologic defects at around the neurula stage. The anterior-posterior axis was shorter than in control embryos. These defects were caused by the abnormal movement of notochord cells. However, the overexpression of HrWnt-5 mRNA did not affect the differentiation of tissues, suggesting that HrWnt-5 solely regulates the morphogenetic movement. Although endogenous HrWnt-5 is expressed in the notochord, the overexpression of HrWnt-5 mRNA caused the defects, suggesting that the amount of HrWnt-5 mRNA in the notochord is strictly regulated. These results suggest that HrWnt-5 regulates the morphogenetic movement of notochord cells during ascidian embryogenesis.

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Expression of a Gene for Major Mitochondrial Protein, ADP/ATP Translocase, during Embryogenesis in the Ascidian Halocynthia roretzi

Cited by 32 publications

References 30 publications

POPK-1/Sad-1 kinase is required for the proper translocation of maternal mRNAs and putative germ plasm at the posterior pole of the ascidian embryo

POPK-1/Sad-1 kinase is required for the proper translocation of maternal mRNAs and putative germ plasm at the posterior pole of the ascidian embryo

Maternal mRNAs ofPEMandmacho 1, the ascidian muscle determinant, associate and move with a rough endoplasmic reticulum network in the egg cortex

Ascidian Wnt‐5 gene is involved in the morphogenetic movement of notochord cells

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