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Galler R, Rydlander L, Riedel N, Kluding H, Edström JE. Balbiani ring induction in phosphate metabolism. Proc Natl Acad Sci U S A 2010; 81:1448-52. [PMID: 16593431 PMCID: PMC344853 DOI: 10.1073/pnas.81.5.1448] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Balbiani rings (BR), giant puffs in Chironomus larval salivary glands, code for giant secretory proteins. As shown earlier, the normally dominant BR2 is turned off with its putative translation product during exposure of larvae to compounds that diminish the stores of P(i). A BR6 develops from a compact chromosome band, and a new giant protein appears in the secretion as the major component. We have determined the sequence of cloned DNA fragments representative for large parts of BR1 and BR2 (normally active) and the inducible BR6. There is an excess of positive charges and high contents of serine/threonine in the coded amino acid composition for the BR1 and BR2 sequences. The coded amino acid sequence for the BR6 clone shares homologies with the others but has an excess of negative charges and lacks serine/threonine. This suggested that the P(i) effects observed earlier could be related to differences in phosphorylation between the normal proteins and the BR6 product. This could be confirmed by measurements of phosphorylation, which occurs in the normal giant proteins mainly at seryl residues. P export with giant secretory protein is normally quantitatively important. Thus, BR6 activation should decrease P loss when P(i) pools are lowered because of inducer action.
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Affiliation(s)
- R Galler
- European Molecular Biology Laboratory, Postfach 10.2209, D-6900 Heidelberg, Federal Republic of Germany
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2
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Arvestad L, Visa N, Lundeberg J, Wieslander L, Savolainen P. Expressed sequence tags from the midgut and an epithelial cell line of Chironomus tentans: annotation, bioinformatic classification of unknown transcripts and analysis of expression levels. INSECT MOLECULAR BIOLOGY 2005; 14:689-95. [PMID: 16313569 DOI: 10.1111/j.1365-2583.2005.00600.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Expressed sequence tags (ESTs) were generated from two Chironomus tentans cDNA libraries, constructed from an embryo epithelial cell line and from larva midgut tissue. 8584 5'-end ESTs were generated and assembled into 3110 tentative unique transcripts, providing the largest contribution of C. tentans sequences to public databases to date. Annotation using Blast gave 1975 (63.5%) transcripts with a significant match in the major gene/protein databases, 1170 with a best match to Anopheles gambiae and 480 to Drosophila melanogaster. 1091 transcripts (35.1%) had no match to any database. Studies of open reading frames suggest that at least 323 of these contain a coding sequence, indicating that a large proportion of the genes in C. tentans belong to previously unknown gene families.
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Affiliation(s)
- L Arvestad
- Stockholm Bioinformatics Center, Abanova University Center, Royal Institute of Technology (KTH), Stockholm, Sweden
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3
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Björk P, Baurén G, Jin S, Tong YG, Bürglin TR, Hellman U, Wieslander L. A novel conserved RNA-binding domain protein, RBD-1, is essential for ribosome biogenesis. Mol Biol Cell 2002; 13:3683-95. [PMID: 12388766 PMCID: PMC129975 DOI: 10.1091/mbc.e02-03-0138] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2002] [Revised: 06/18/2002] [Accepted: 07/22/2002] [Indexed: 11/11/2022] Open
Abstract
Synthesis of the ribosomal subunits from pre-rRNA requires a large number of trans-acting proteins and small nucleolar ribonucleoprotein particles to execute base modifications, RNA cleavages, and structural rearrangements. We have characterized a novel protein, RNA-binding domain-1 (RBD-1), that is involved in ribosome biogenesis. This protein contains six consensus RNA-binding domains and is conserved as to sequence, domain organization, and cellular location from yeast to human. RBD-1 is essential in Caenorhabditis elegans. In the dipteran Chironomus tentans, RBD-1 (Ct-RBD-1) binds pre-rRNA in vitro and anti-Ct-RBD-1 antibodies repress pre-rRNA processing in vivo. Ct-RBD-1 is mainly located in the nucleolus in an RNA polymerase I transcription-dependent manner, but it is also present in discrete foci in the interchromatin and in the cytoplasm. In cytoplasmic extracts, 20-30% of Ct-RBD-1 is associated with ribosomes and, preferentially, with the 40S ribosomal subunit. Our data suggest that RBD-1 plays a role in structurally coordinating pre-rRNA during ribosome biogenesis and that this function is conserved in all eukaryotes.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden
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4
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Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
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5
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Baurén G, Belikov S, Wieslander L. Transcriptional termination in the Balbiani ring 1 gene is closely coupled to 3'-end formation and excision of the 3'-terminal intron. Genes Dev 1998; 12:2759-69. [PMID: 9732273 PMCID: PMC317118 DOI: 10.1101/gad.12.17.2759] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
We have analyzed transcription termination, 3'-end formation, and excision of the 3'-terminal intron in vivo in the Balbiani ring 1 (BR1) gene and its pre-mRNA. We show that full-length RNA transcripts are evenly spaced on the gene from a position 300 bp upstream to a region 500-700 bp downstream of the polyadenylation sequence. Very few full-length transcripts and no short, cleaved, nascent transcripts could be observed downstream of this region. Pre-mRNA with 10-20 adenylate residues accumulates at the active gene and then rapidly leaves from the gene locus. Only polyadenylated pre-mRNAs could be detected in the nucleoplasm. Our results are consistent with the hypothesis that transcription termination occurs in a narrow region for the majority of transcripts, simultaneous with 3'-end formation. Excision of the 3'-terminal intron occurs before 3'-end formation in about 5% of the nascent transcripts. When transcription terminates, 3' cleavage takes place and 10-20 adenylate residues are added, the 3'-terminal intron is excised from additionally about 75% of the pre-mRNA at the gene locus. Our data support a close temporal and spatial coupling of transcription termination and the cleavage and initial polyadenylation of 3'-end formation. Excision of the 3'-terminal intron is highly stimulated as the cleavage/polyadenylation complex assembles and 3'-end formation is initiated.
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Affiliation(s)
- G Baurén
- Department of Molecular Genome Research, Stockholm University, S-106 91 Stockholm, Sweden
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6
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Galli J, Wieslander L. Structure of the smallest salivary-gland secretory protein gene in Chironomus tentans. J Mol Evol 1994; 38:482-8. [PMID: 8028027 DOI: 10.1007/bf00178848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The salivary gland secretion in the dipteran Chironomus tentans is composed of approximately 15 different secretory proteins. The most well known of the corresponding genes are the four closely related Balbiani ring (BR) genes, in which the main part of each approximately 40-kb gene is composed of tandemly arranged repetitive units. Six of the seven additional secretory protein genes described share structural similarities with the BR genes and are members of the same BR multigene family. Here we report the identification of a new secretory protein gene, the sp12 gene, encoding the smallest component of the C. tentans salivary gland secretion. The gene has a corresponding mRNA length of approximately 0.7 kb and codes for a protein with a calculated molecular weight of 7,619 Da. The sp12 gene was characterized in seven Chironomus species. Based on a comparison of the orthologous gene sequences, we conclude that the sp12 gene has a repetitive structure consisting of diverged 21-bp-long repeats. The repeat structure and the codon composition are similar to the so-called SR regions of the BR genes and the sp12 gene may represent a diverged member of the BR multigene family.
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Affiliation(s)
- J Galli
- Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden
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7
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Wieslander L. The Balbiani ring multigene family: coding repetitive sequences and evolution of a tissue-specific cell function. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1994; 48:275-313. [PMID: 7938551 DOI: 10.1016/s0079-6603(08)60858-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- L Wieslander
- Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden
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8
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Galli J, Wieslander L. A new member of the balbiani ring multigene family in the dipteran Chironomus tentans consists of a single-copy version of a unit repeated in other gene family members. J Mol Evol 1993; 37:457-63. [PMID: 8283477 DOI: 10.1007/bf00160426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The known Balbiani ring (BR) multigene family members in the dipteran Chironomus tentans encode salivary gland secretory proteins in the size range between 38 and 1,000 kDa. The proteins interact to form protein fibers used by the aquatic larvae to spin feeding and protective larval tubes or pupation tubes. Here, we describe a new BR multigene family member, the sp17 gene, which codes for an 89-amino-acid-long protein with a relative mobility of 17k. The gene has a high content of charged amino acid residues and consists of two structurally different halves. Five regularly spaced cysteine codons are present in the 5' half while the 3' half contains five proline codons. These two different halves exhibit similarities to the C and SR regions, respectively, which form the tandemly repeated units in the about 40-kb-long BR genes and which also, in different versions, are the building blocks of all genes in the BR multigene family. In this multigene family, encoding interacting structural proteins, the long BR genes with their 125-150 tandemly arranged repeat units as well as the short sp17 gene with its single-copy version of such a repeat unit, have therefore evolved from a common ancestor.
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Affiliation(s)
- J Galli
- Department of Cell and Molecular Biology, Medical Nobel Institut Karolinska Institutet, Stockholm, Sweden
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9
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Paulsson G, Höög C, Bernholm K, Wieslander L. Balbiani ring 1 gene in Chironomus tentans. Sequence organization and dynamics of a coding minisatellite. J Mol Biol 1992; 225:349-61. [PMID: 1593624 DOI: 10.1016/0022-2836(92)90926-b] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Balbiani ring (BR) genes in diptera encode large secretory proteins and are classical model systems for studies of gene expression. In Chironomus tentans, four closely related BR genes, BR 1, BR 2.1, BR 2.2 and BR 6 form a gene family. The BR genes have been partially characterized and are known to contain long arrays of tandemly arranged repeat units with an hierarchical repeat organization. Here, we report the sequence organization of the complete transcribed part of the BR 1 gene in C. tentans. The gene contains five exons and four introns. Three of the introns are located at the 5' end and the fourth at the 3' end of the gene. Exon 4 is approximately 35,000 bases long and is built completely from tandemly organized repeats. We show that this long repeat block contains two types of related repeat units, beta and gamma. Each type forms a large uninterrupted array, a 5' beta array and a 3' gamma array with a sharp border between them. In the hierarchical repeat structure in each repeat array, all repeats are virtually identical at one level of repetition, but shown differences at the next level. The whole repeat block in the BR 1 gene fluctuates in size between different alleles, but not by more than 10%. In contrast, within the block, the beta and gamma arrays vary in length between 8000 and 29,000 bases in an inverse fashion, together keeping the overall length requirement. We propose that the length of exon 4 is conserved by selection of cross-over products of a given length, and that the internal hierarchical sequence organization in the BR 1 gene is a consequence of the combined action of several different sequence turnover mechanisms, all dependent on the unequal pairing of homologous sequences at different, competing levels of repetition.
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Affiliation(s)
- G Paulsson
- Department of Molecular Genetics, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden
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10
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Wieslander L, Paulsson G. Sequence organization of the Balbiani ring 2.1 gene in Chironomus tentans. Proc Natl Acad Sci U S A 1992; 89:4578-82. [PMID: 1584794 PMCID: PMC49126 DOI: 10.1073/pnas.89.10.4578] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Balbiani rings are giant chromosomal puffs, containing related genes that provide unique possibilities for in vivo analysis of gene expression at the chromatin and ribonucleoprotein levels. Here, the 5' end of the Balbiani ring 2.1 gene in the dipteran Chironomus tentans has been isolated and the sequence organization of the entire Balbiani ring gene is presented. The gene contains five exons, one being extremely small, only 6 base pairs, and one being extremely large, approximately 30 kilobase pairs. Three introns are located at the 5' end and a fourth one is located at the 3' end. The central 30-kilobase-pair exon is entirely built from tandemly organized repeats. All repeats are virtually identical except for a few variant repeats at both ends of the repeat array. The number of repeats may vary between alleles and the length of the gene therefore changes between 30 and 35 kilobase pairs.
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Affiliation(s)
- L Wieslander
- Department of Molecular Genetics, Medical Nobel Institute Karolinska Institutet, Stockholm, Sweden
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11
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Case ST, Wieslander L. Secretory proteins of Chironomus salivary glands: structural motifs and assembly characteristics of a novel biopolymer. Results Probl Cell Differ 1992; 19:187-226. [PMID: 1289993 DOI: 10.1007/978-3-540-47207-0_7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Salivary glands of Chironomus synthesize a family of at least ten secretory proteins that can be grouped into three size classes: the large (about 1000 kDa), intermediate (100- to 200 kDa), and small (less than 100 kDa). After synthesis, secretory proteins undergo a dramatic transformation to form a novel biopolymer. Secretory proteins accumulate in the central lumen of the gland, forming dissociable complexes that appear as a network of smooth fibrils and multistranded beaded fibers. When secretory protein complexes are extruded through the secretory duct, the fibers become oriented in parallel arrays; when these parallel arrays of fibers emerge from the mouth of larvae they are an insoluble, silk-like thread. Regulation of secretory protein-coding gene expression determines which secretory proteins are synthesized, thus, the composition of silk threads. At least two types of threads are produced: larval silk is used to construct tubes for protective housing and assist with feeding; prepupal silk is used to construct tubes for larval/pupal ecdysis (pupation). Variations in composition presumably contribute to different mechanical properties of larval and prepupal silk threads. Since the macroscopic physical properties of polymerized silk most likely reflect the microscopic structure and interaction of secretory proteins, it becomes important to learn the principles which govern secretory protein assembly at the molecular level. Which secretory proteins interact and what are the sites used for intraportein and protein-protein interactions during the assembly of this biopolymer? All eight secretory proteins characterized thus far contain tandemly repeated peptide sequences (ranging from 14-90 amino acids in length) and/or a periodic distribution of Cys residues. These motifs appear to be unique; no other biopolymer has either the repeated peptide sequences or composite structure of chironomid silk threads. The evolutionary conservation of motifs within repeats and among different secretory proteins suggests that the sequences and three-dimensional structures of the motifs may be important for assembly of secretory proteins into complexes, oriented fibers, and silk threads. Further study of secretory protein assembly will bring us closer to understanding how this silk assembles in vivo. By learning principles that nature employs to construct such a novel composite biopolymer, it may become feasible to design and produce new classes of fibers or biomolecular materials with distinctive properties that are currently unavailable.
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Affiliation(s)
- S T Case
- Department of Biochemistry, University of Mississippi Medical Center, Jackson 39216-4505
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12
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Galactose-induced puffing changes inChironomus thummi Balbiani rings and their dependence on protein synthesis. Chromosoma 1990. [DOI: 10.1007/bf01737290] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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13
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Induction of balbiani ring puffing changes by sugars and alcohols in Chironomus thummi. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0020-1790(90)90035-s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Cortés E, Botella LM, Barettino D, Díez JL. Identification of the spI products of Balbiani ring genes in Chironomus thummi. Chromosoma 1989; 98:428-32. [PMID: 2627801 DOI: 10.1007/bf00292788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The spI fraction of high molecular weight secretory proteins was analysed in Chironomus thummi. These proteins are encoded by giant Balbiani ring (BR) genes which develop specifically in salivary gland cells. Each component of the spI fraction was studied electrophoretically from early and middle 4th instar larvae and prepupae, as well from galactose-treated larvae where changes in the relative puffing pattern of BR1 and BR2 are known to occur. The spI fraction consists of at least two bands with electrophoretic mobilities slower than those of the spI components of Camptochironomus. The slow migrating component remains throughout the 4th larval instar, while the amount of the faster component changes, being abundant in early 4th instar and prepupae, but not present (or very weak) in middle 4th instar. The correlated shifts in BR puffing pattern during these developmental stages suggest that the slow and fast components are encoded by BR2 and BR1. The spI fraction is modified by galactose treatment, the fast component being induced in parallel with a decrease in the slow component. These changes are correlated with changes in the steady-state levels of RNA: an increase in BR1 RNA and a decrease in BR2 RNA, and of proteins. These proteins could correspond to the spIb and spIa fractions allocated to BR2 and BR1, respectively, in Camptochironomus. After galactose treatment a new faster band sometimes appears, that could correspond to the spIc fraction of Camptochironomus. A possible spId equivalent was also identified. In conclusion the main features of the spI family in C. thummi are similar to those of spI in Camptochironomus.
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Affiliation(s)
- E Cortés
- Centro de Investigaciones Biológicas (C.S.I.C.), Madrid, Spain
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15
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Dignam SS, Yang L, Lezzi M, Case ST. Identification of a Developmentally Regulated Gene for a 140-kDa Secretory Protein in Salivary Glands of Chironomus tentans Larvae. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)60552-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Dreesen TD, Lezzi M, Case ST. Developmentally regulated expression of a Balbiani ring 1 gene for a 180-kD secretory polypeptide in Chironomus tentans salivary glands before larval/pupal ecdysis. J Biophys Biochem Cytol 1988; 106:21-7. [PMID: 3339088 PMCID: PMC2114959 DOI: 10.1083/jcb.106.1.21] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The expression of a Balbiani ring 1 gene that codes for a salivary gland-specific 180-kD secretory polypeptide (sp180) is regulated developmentally. Immunoblots of salivary gland protein incubated with an affinity-purified nonapeptide-reactive antibody demonstrated that the salivary gland content of sp180 increases as much as 10-fold between stages 8 and 10 of the fourth larval instar. Hybridization of RNA dot-blots with an oligonucleotide probe indicated that the observed increase in sp180 was preceded by a parallel 20-fold increase in the steady state level of its mRNA beginning between stages 7 and 8. In vitro nuclear transcription experiments demonstrated that there was a 10-fold acceleration in the rate of sp180 gene transcription between stages 6 and 10. The limited period of expression of the sp180 gene contrasted dramatically with the expression of Balbiani ring genes BR1, BR2 alpha, BR2 beta, and BR6, which code for the sp-I family of fibrous secretory polypeptides. The appearance of sp180 in secretion coincided with microscopically visible changes in the bundling of these fibrous polypeptides. At the same time, we noticed changes in the appearance and consistency of feeding tubes that larvae construct with this secretion. These results lead us to propose that sp180 may modify the structure or utilization of fibrous secretory polypeptides specifically for the assembly of pupation tubes necessary for larval/pupal ecdysis.
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Affiliation(s)
- T D Dreesen
- Department of Biochemistry, University of Mississippi Medical Center, Jackson 39216-4505
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17
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Lendahl U, Wieslander L. Balbiani ring (BR) genes exhibit different patterns of expression during development. Dev Biol 1987. [DOI: 10.1016/0012-1606(87)90146-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Dreesen TD, Case ST. A peptide-reactive antibody to a Balbiani ring gene product: immunological evidence that a 6.5-kb RNA in Chironomus tentans salivary glands is mRNA for a 180-kDa nonfibrous component of larval secretion. Gene 1987; 55:55-65. [PMID: 3623106 DOI: 10.1016/0378-1119(87)90248-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An immunological approach was utilized to demonstrate that a tissue-specific Balbiani ring (BR) transcript in Chironomus tentans is the mRNA for a secreted 180-kDa polypeptide. Balbiani ring 1 (BR1) on the polytene chromosome IV of larval salivary glands contains a gene comprised of tandemly duplicated nucleotide sequences that are transcribed into a salivary gland-specific, 6.5-kb poly(A)+RNA for which a partial cDNA sequence exists [Dreesen et al., J. Biol. Chem. 260 (1985) 11824-11830]. A nonapeptide was synthesized so that its amino acid sequence corresponded to an open reading frame in the cDNA. This peptide was used to raise rabbit polyclonal antisera and to purify the peptide-reactive antibody by affinity chromatography. The affinity-purified antibody bound specifically to a 180-kDa polypeptide on Western blots containing extracts of total salivary gland protein. Western blot analysis of microdissected cellular vs. lumenal fractions of salivary glands indicated that this 180-kDa polypeptide was primarily localized in the lumen. Consequently, this polypeptide was designated a secretory polypeptide (sp180). Finally, the peptide-reactive antibody was used to localize sp180 in a nonfibrous component of salivary gland secretion by indirect immunofluorescence microscopy.
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Case ST. Correlated changes in steady-state levels of Balbiani ring mRNAs and secretory polypeptides in salivary glands of Chironomus tentans. Chromosoma 1986; 94:483-91. [PMID: 3829833 DOI: 10.1007/bf00292758] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Balbiani rings (BRs) on polytenized chromosomes in Chironomid salivary glands contain members of a homologous multigene family that encodes a family (the sp-I family) of high Mr secretory polypeptides. Each of these BR genes is comprised largely of tandemly duplicated core repeat sequences consisting of related constant (C) regions and intergenically divergent subrepeat (SR) regions. A set of oligodeoxyribonucleotide probes were synthesized that correspond to the transcribed strand of the SR region of BR1, BR2 alpha, BR2 beta, and BR6 core repeats. Under a defined set of conditions, it was possible to show that each oligonucleotide probe hybridized exclusively to its cognate repeat type without hybridization to other repeat types in cloned DNA templates. These BR probes were then used in dot-blot hybridization experiments to simultaneously follow alterations in the steady-state level of BR mRNAs in response to prolonged exposure of larvae to galactose. The results indicated that the relative amounts of these four BR mRNAs may change in a noncoordinate manner. These BR probes were also used in experiments to compare simultaneously the salivary gland content of sp-I components and specific BR mRNAs in larvae that exhibited naturally occurring or induced alterations in BR gene expression. A correlation was found which suggested that sp-Ia is encoded in a gene comprised of BR1 repeats, sp-Ib is encoded by BR2 beta repeats, sp-Ic is encoded by BR6 repeats and sp-Id is encoded by BR2 alpha repeats.
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20
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Kao WY, Case ST. Individual variations in the content of giant secretory polypeptides in salivary glands of Chironomus. Chromosoma 1986; 94:475-82. [PMID: 3829832 DOI: 10.1007/bf00292757] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Salivary glands in aquatic larvae of Chironomus are responsible for formation of a fiber that larvae use to construct feeding tubes. Major constituents of this fiber include a family (the sp-I family) of high Mr (1 X 10(6) secretory polypeptides. Because of our interest in the polypeptide composition and polymerization of the salivary fiber we conducted a survey of the electrophoretic pattern of sp-I components found in salivary glands obtained from individual larvae. The survey encompassed ten strains of Chironomus tentans, three strains of Chironomus pallidivittatus and four strains of Chironomus thummi. Salivary glands from C. tentans and C. pallidivittatus contained at least four sp-I components (sp-Ia, sp-Ib, sp-Ic and sp-Id) that behave identically with regard to their electrophoretic mobility and detectability when larvae were exposed to galactose or glycerol. Sp-I components in C. thummi were generally fewer and not directly comparable by electrophoretic mobility to sp-I components in the other two species. During this survey two important alterations were observed in the electrophoretic pattern of sp-I components obtained from C. tentans and C. pallidivittatus. First, all four sp-I components exhibited, with a low frequency, double bands that appeared as slow-versus-fast electrophoretic variants of a particular component. Secondly, the relative steady-state level of each sp-I component fluctuated in comparison to other sp-I components in the same extract. This fluctuation varied such that any one sp-I component might appear as a single prominent component.(ABSTRACT TRUNCATED AT 250 WORDS)
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21
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Kao WY, Case ST. A novel giant secretion polypeptide in Chironomus salivary glands: implications for another Balbiani ring gene. J Biophys Biochem Cytol 1985; 101:1044-51. [PMID: 4030890 PMCID: PMC2113727 DOI: 10.1083/jcb.101.3.1044] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chironomus salivary glands contain a family of high Mr (approximately 1,000 X 10(3)) secretion polypeptides thought to consist of three components: sp-Ia, sp-Ib, and sp-Ic. The use of a new extraction protocol revealed a novel high Mr component, sp-Id. Results of a survey of individual salivary glands indicated that sp-Id was widespread in more than a dozen strains of C. tentans and C. pallidivittatus. Sp-Id was phosphorylated at Ser residues, and a comparison of cyanogen bromide and tryptic peptide maps of 32P-labeled polypeptides suggested that sp-Ia, sp-Ib, and sp-Id are comprised of similar but nonidentical tandemly repeated amino acid sequences. We concluded that sp-Id is encoded by an mRNA whose size and nucleotide sequence organization are similar to Balbiani ring (BR) mRNAs that code for the other sp-I components. Furthermore, parallel repression of sp-Ib and sp-Id synthesis by galactose led us to hypothesize that both of their genes exist within Balbiani ring 2.
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Yagi S. Effects of ligation on ethanol-induced Balbiani ring puffing in salivary glands of Chironomus. Chromosoma 1984. [DOI: 10.1007/bf00292474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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