G Protein α Subunit Genes in Octopus Photoreceptor Cells

Iwasa, Takeshi; Yanai, Takanori; Nakagawa, Masashi; Kikkawa, Shōichi; Obata, Shuichi; Usukura, Jiro; Tsuda, Motoyuki

doi:10.2108/zsj.17.711

Cited by 5 publications

(5 citation statements)

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“…Total RNA concentrations of head, trunk, and tail preparations showed no remarkable difference in normal and epitoke specimens (0.44-1.30 μg total RNA/mg tissue). The amount of mRNA of G proteins was compared by two-step RT-PCR with degenerated PCR primers designed according to the conserved amino acid motifs of Gα (Iwasa et al 2000).…”

Section: Comparison Of Gα Mrna In Normal and Epitoke Specimensmentioning

confidence: 99%

Ultrastructure and localization of a visual Gq protein in ied epitoke ocelli of Perinereis brevicirris (Polychaeta, Annelida)

2005

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Functional ultrastructural changes in the rhabdomeric photoreceptors of the cerebral ocelli are described for normal and sexually mature (epitoke) Perinereis brevicirris (Polychaeta, Annelida). With sexual maturation, the cerebral ocelli hypertrophied, increasing in volume to 5.5 times that of ocelli in the normal state, and the thickness of the retinal layer increased up to 10 times. Perinereis ocelli have a pigmented retinal layer consisting of at least two cell types: photoreceptor cell (PR) and pigmented supporting cells (PS). In epitoke ocelli, PR bear well-developed rhabdomeric microvilli, multilamellar bodies, and numerous cytoplasmic membranous structures, including vesicles, smooth endoplasmic reticulum, and secondary lysosomes. Localization of a visual Gq protein in the ocelli was studied with anti-GqC antibody. The antibody strongly labeled not only microvilli and multilamellar bodies throughout the retinal layer, but also secondary lysosomes and vesicles in the cytoplasm of the PR in the epitoke ocelli, although labeling was observed only in the microvilli and multilamellar bodies in normal ocelli. Reverse transcription/polymerase chain reaction analysis revealed that the amount of G protein alpha subunit mRNA in the epitoke head increased by roughly twice that of the normal head. Since Gq protein is essential for phototransduction in Perinereis ocelli, these results suggest that the sites are involved in photoreceptive membrane turnover, which occurs much more extensively in epitoke ocelli. Thus, epitoke ocelli may represent a model system for studying rhabdomeric photoreceptive membrane turnover.

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Section: Comparison Of Gα Mrna In Normal and Epitoke Specimensmentioning

confidence: 99%

Ultrastructure and localization of a visual Gq protein in ied epitoke ocelli of Perinereis brevicirris (Polychaeta, Annelida)

2005

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“…The total RNA was prepared from the C. intestinalis larvae, and a cDNA library was constructed with a λ ZAP vector (Stratagene, La Jolla, USA), as described previously (Iwasa et al , 2000). The cDNA library was directly used as a template to amplify the cDNA fragments of about 500 bp encoding the G protein α subunits by polymerase chain reaction (PCR), using a pair of degenerate oligonucleotide primers corresponding to two conserved amino acid sequences, KQM(K/R)IIH and KWI(H/Q)CF, respectively.…”

Section: Isolation and Sequencing Of Cdna Clones Encoding G Protein αmentioning

confidence: 99%

“…The cDNA library was directly used as a template to amplify the cDNA fragments of about 500 bp encoding the G protein α subunits by polymerase chain reaction (PCR), using a pair of degenerate oligonucleotide primers corresponding to two conserved amino acid sequences, KQM(K/R)IIH and KWI(H/Q)CF, respectively. The 5'and 3'-portions of cDNAs were amplified from the cDNA library by PCR using a gene-specific primer and a vector primer, as described previously (Iwasa et al , 2000). Full-length cDNA clones were amplified by PCR using a thermostable DNA polymerase bearing proofreading activity (Takara LA Taq; Takara Shuzo, Japan), with primers corresponding to the 5'-and 3'-untranslated region (UTR) sequences of cDNAs (5'-ATACGAGCAAGCACAGCGGGAA-3' for 5'-UTR, and 5'-TATGCATGCGATGACGTCAC-3' for 3'-UTR).…”

Section: Isolation and Sequencing Of Cdna Clones Encoding G Protein αmentioning

confidence: 99%

“…Mammals have at least 17 functional Gα genes, several of which are spliced alternatively, that encode 23 distinct protein products (Nürnberg et al, 1995). The presence of multiple Gα isoforms has also been demonstrated in various invertebrates, including insects, nematodes, octopus, hydra, and sponges (Wilkie and Yokoyama, 1994;Suga et al, 1999;Iwasa et al, 2000). Metazoan Gα subunits can be classified into G s , G i , G q , and G 12 classes (Simon et al, 1991;Suga et al, 1999).…”

Section: Diversity Of Gα α α α Isoforms In Ascidiansmentioning

confidence: 99%

“…All three G i class members of Ciona belong to the Gα i subfamily, and so far no ascidian Gα isoforms have been assigned to the Gα t , Gα o , and Gα z subfamilies. Since Gα o isoforms have been reported in diverse invertebrate phyla, including sponges (Suga et al, 1999), arthropods (Thambi et al, 1989;Horgan et al, 1995), and molluscs (Kojima et al, 1997;Iwasa et al, 2000), it is likely that ascidians also have this isoform. G o is abundant in the CNS both in vertebrates (Strathmann et al, 1990) and in insects (Thambi et al, 1989;Horgan et al, 1995), and play important roles in the function and development of the nervous systems (Offermanns 2001).…”

Section: Diversity Of Gα α α α Isoforms In Ascidiansmentioning

confidence: 99%

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Central Nervous System-specific Expression of G Protein α Subunits in the Ascidian Ciona intestinalis

et al. 2002

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Heterotrimeric G proteins play crucial roles as mediators of signaling by many extracellular stimuli. The receptors that activate G proteins constitute the largest and most diverse family of cell surface molecules involved in signal transmission of metazoan cells. To investigate G protein signaling in the central nervous system (CNS) of chordates, we isolated cDNA fragments encoding five different G protein alpha subunits (CiGalpha(x), CiGalpha(q), CiGalpha(i1a), CiGalpha(i1b), and CiGalpha(i2)) from larvae of the ascidian, a simple chordate, Ciona intestinalis. In situ hybridization analysis revealed that each isoform had distinct patterns of spatial distribution in embryos. Among them, CiGalpha(i1a) and CiG alpha(i1b) mRNAs were specifically expressed in the CNS of the larva, whereas CiGalpha(q) transcripts were expressed in small parts of the trunk epidermis and the tip of the tail, but not in the CNS. The CiGalpha(x) expression was widely observed throughout the trunk and tail of the embryos, and the signals were stronger in the epidermis, mesenchyme, and tail muscle cells. Comparison of cDNA sequences and the exon-intron organization indicate that CiGalpha(i1a) and CiGalpha(i1b) are produced by alternative splicing of transcripts from a single gene, CiGalpha(i1). In the cleavage and gastrula stages, transcripts of CiGalpha(i1) were widely distributed in embryos, and the expression then became restricted to the CNS of tailbud embryos and larvae. An exhaustive search has failed to find transducin-type alpha subunits in C. intestinalis. Since CiGalpha(i1) is expressed in the ocellus, CiGalpha(i1) may mediate signals from Ci-opsin1, a visual pigment of the ocellus photoreceptor cells.

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Heterotrimeric G Protein α and β Subunit Genes of the Ascidian, Halocynthia roretzi

Iwasa

Kanehara

Watari

et al. 2001

The Biology of Ascidians

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G Protein α Subunit Genes in Octopus Photoreceptor Cells

Cited by 5 publications

References 44 publications

Ultrastructure and localization of a visual Gq protein in ied epitoke ocelli of Perinereis brevicirris (Polychaeta, Annelida)

Ultrastructure and localization of a visual Gq protein in ied epitoke ocelli of Perinereis brevicirris (Polychaeta, Annelida)

Central Nervous System-specific Expression of G Protein α Subunits in the Ascidian Ciona intestinalis

Heterotrimeric G Protein α and β Subunit Genes of the Ascidian, Halocynthia roretzi

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