The Balbiani ring 3 gene in Chironomus tentans has a diverged repetitive structure split by many introns

Paulsson, Gabrielle; Lendahl, Urban; Galli, Joakim; Ericsson, Christer; Wieslander, Lars

doi:10.1016/0022-2836(90)90355-p

Cited by 36 publications

(38 citation statements)

References 63 publications

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“…BR3 protein is secreted in an enormous amount by salivary glands of an aquatic larvae of the midge Chironomus and it is used to weave a tube in which an aquatic larva houses itself. In preparations of Chironomus polytene salivary gland chromosomes, a gene encoding BR3 is readily recognized as an enlarged RNA puff (Balbiani Ring) reflecting its enormous transcriptional activity, and BR3 protein too is encoded by a coding sequence that is made of tandem repeats (6,19). As shown in the alignments of Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The codon usage of the T. harzianum qid74 gene resembles that of other Trichoderma genes that in the induced state demonstrated a very high transcription rate (14). Out of the 61 codons, 6 were not used at all whereas 24 were used 10 or more times. For example, of 76 glycine residues, 47 were encoded by the same triplet.…”

Section: Resultsmentioning

confidence: 99%

“…Whereas larvae of the first suborder tend to lead aquatic lives, those of the second suborder are terrestrial. Indeed, no gene homologous to that encoding BR3 was found within the Drosophila genome (6,19). Thus it would appear that BR3 gene also arose de novo either within the suborder Nematocera or much later within the genus Chironomus.…”

Section: Discussionmentioning

confidence: 99%

“…Such apparent convergence of a protein part, however, has been interpreted as consequences of domain exchanges between unrelated proteins because of exon shufflings (5,6). Nevertheless, how, by exon shufflings, the same domain can be propagated to be included in a number of unrelated proteins has never been made clear.…”

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confidence: 99%

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Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus

Rey

Ohno

Pintor‐Toro

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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A gene, qid74, of mycoparasitic filamentous fungus Trichoderma harzianum and its allies encodes a cell wall protein that is induced by replacing glucose in the culture medium with chitin (simulated mycoparasitism conditions). Because no trace of this gene can be detected in related species such as Gibberella fujikuroi and Saccharomyces cerevisiae, the qid74 gene appears to have arisen de novo within the genus Trichoderma. Qid74 protein, 687 residues long, is now seen as highly conserved tandem repeats of the 59-residue-long unit. This unit itself, however, may have arisen as tandem repeats of the shorter 13-residue-long basic unit. Within the genus Trichoderma, the amino acid sequence of Qid74 proteins has been conserved in toto. The most striking is the fact that Qid74 shares 25.3% sequence identity with the carboxyl-terminal half of the 1,572-residue-long BR3 protein of the dipteran insect Chironomus tentans. BR3 protein is secreted by the salivary gland of each aquatic larva of Chironomus to form a tube to house itself. Furthermore, the consensus sequence derived from these 59-residue-long repeating units resembles those of epidermal growth factor-like domains found in divergent invertebrate and vertebrate proteins as to the positions of critical cysteine residues and homology of residues surrounding these cysteines.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus

Rey

Ohno

Pintor‐Toro

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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“…First, hnRNP proteins and snRNPs (plus other splicing factors) occur in the same nuclear extrachromosomal complexes, the B snurposomes, and second, these same components occur on almost all lampbrush chromosome loops in amounts that correlate with RNA mass distribution on that loop (5). Although reports of snRNPs at loci thought not to have introns [Chironomus polytene chromosome Balbiani rings (4) and newt histone gene-containing lampbrush loops (5)] appear to support this model, it is now known that the Balbiani ring genes contain introns (16,17), and splicing signals may occur on extremely long (hundreds of kilobases) readthrough transcription units on lampbrush chromosomes (18 …”

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confidence: 88%

Independent deposition of heterogeneous nuclear ribonucleoproteins and small nuclear ribonucleoprotein particles at sites of transcription.

Amero

Raychaudhuri

Cass

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

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The major nuclear ribonucleoproteins (RNPs) involved in pre-mRNA processing are classified in broad terms either as small nuclear RNPs (snRNPs), which are major participants in the splicing reaction, or heterogeneous nuclear RNPs (hnRNPs), which traditionally have been thought to function in general pre-mRNA packaging. We obtained antibodies that recognize these two classes of RNP in Drosophila melanogaster. Using a sequential immunostaining technique to compare directly the distribution of these RNPs on Drosophila polytene chromosomes, we found that the two patterns were very similar qualitatively but not quantitatively, arguing for the independent deposition of the two RNP types and supporting a role for hnRNP proteins, but not snRNPs, in general transcript packaging.Both heterogeneous nuclear ribonucleoproteins (hnRNPs; reviewed in refs. 1 and 2) and small nuclear ribonucleoproteins (snRNPs; reviewed in ref.3) are deposited cotranscriptionally on eukaryotic RNA polymerase II transcripts (4-8). Whereas the major basic hnRNP proteins have been considered traditionally to function in general pre-mRNA packaging (2, 9), they have been proposed recently to be specific splicing cofactors or to be preferentially associated with splice junction sequences (10-15). snRNPs are major participants in the splicing reaction (3) but have been implicated recently in general packaging as part of a previously assembled unitary processing complex also containing hnRNPs (5, 6). The various proposals predict different amounts and ratios of the two protein types on nuclear pre-mRNA molecules at chromosomal sites of transcription, which is the issue we have addressed by sequential immunostaining.The core hnRNP proteins (A, B, and C proteins of 32-45 kDa) were originally identified as the major proteins that are associated with newly synthesized pre-mRNA (in the form of 30-50S RNP particles) when it is extracted from nuclei (reviewed in refs. 1 and 2). This observation, together with their nuclear abundance, their ability to bind single-stranded nucleic acids regardless of sequence, and their helixdestabilizing properties, led to the notion that these core hnRNP proteins are involved in general pre-mRNA packaging, much as the histones are involved in the general packaging of DNA (1, 2). However, more recent investigations of hnRNP proteins, using in vitro splicing or in vitro RNA binding studies, have suggested that these proteins play a role in the splicing reaction (10-12), that they bind with high affinity to sequences at 3' splice sites (13,14), and that they are dependent on snRNPs for acquisition of a crosslinkable association with RNA (13). These in vitro studies have led to a reappraisal of the independent structural role of hnRNP proteins in pre-mRNA packaging towards a view that they are a few of the many required cofactors for splicing. The simplest version of this view would predict a constant stoichiometry of snRNPs and the core hnRNP proteins on pre-mRNA, in amounts that correlate with the number of splicing sign...

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A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases.

Joukov¹,

Pajusola²,

Kaipainen³

et al. 1996

The EMBO Journal

1,414

965

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Angiogenesis, the sprouting of new blood vessels from pre‐existing ones, and the permeability of blood vessels are regulated by vascular endothelial growth factor (VEGF) via its two known receptors Flt1 (VEGFR‐1) and KDR/Flk‐1 (VEGFR‐2). The Flt4 receptor tyrosine kinase is related to the VEGF receptors, but does not bind VEGF and its expression becomes restricted mainly to lymphatic endothelia during development. In this study, we have purified the Flt4 ligand, VEGF‐C, and cloned its cDNA from human prostatic carcinoma cells. While VEGF‐C is homologous to other members of the VEGF/platelet derived growth factor (PDGF) family, its C‐terminal half contains extra cysteine‐rich motifs characteristic of a protein component of silk produced by the larval salivary glands of the midge, Chironomus tentans. VEGF‐C is proteolytically processed, binds Flt4, which we rename as VEGFR‐3 and induces tyrosine autophosphorylation of VEGFR‐3 and VEGFR‐2. In addition, VEGF‐C stimulated the migration of bovine capillary endothelial cells in collagen gel. VEGF‐C is thus a novel regulator of endothelia, and its effects may extend beyond the lymphatic system, where Flt4 is expressed.

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The Balbiani ring 3 gene in Chironomus tentans has a diverged repetitive structure split by many introns

Cited by 36 publications

References 63 publications

Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus

Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus

Independent deposition of heterogeneous nuclear ribonucleoproteins and small nuclear ribonucleoprotein particles at sites of transcription.

A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases.

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