Proportionate representation of rDNA and Balbiani ring DNA in polytene chromosomes of Chironomus tentans

Chromosoma ◽  
1976 ◽  
Vol 57 (2) ◽  
pp. 185-197 ◽  
Author(s):  
C. P. Hollenberg
Keyword(s):  
Polytene Chromosomes ◽  
Chironomus Tentans ◽  
Balbiani Ring

The 3-D substructure of RNA in nascent RNP granules: A novel application of osmium ammine-B staining and electron spectroscopic imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 504-505
Author(s):  
Ada L. Olins ◽  
Donald E. Olins ◽  
Manesh B. Shah ◽  
Henri A. Levy ◽  
David P. Bazett-Jonest
Keyword(s):  
Salivary Gland ◽  
Polytene Chromosomes ◽  
Spectroscopic Imaging ◽  
Secretory Proteins ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Electron Spectroscopic Imaging ◽  
Nuclear Pores ◽  
Rnp Granules

RNA has a particulate substructure when visualized in situ with the nucleic acid specific stain osmium ammine-B (OA-B). In this study energy spectroscopic imaging (ESI) was used to enhance the contrast and collect the data for tomographic reconstructions.The Balbiani ring (BR) in the salivary gland polytene chromosomes of Chironomus tentans larvae furnishes a well known model for the structure of nascent m-RNA. This gland produces copious amounts of silk-like secretory proteins which are very large (106 daltons). The site of transcription, the BR, is easily recognized in the EM by its characteristic “puff” structure and electron-dense granular transcripts. Mature BR granules are 45-50 nm in diameter and can be easily observed within the nucleus and passing through nuclear pores.

A structural analysis of Balbiani ring DNA sequences in Chironomus tentans

Chromosoma ◽  
1981 ◽  
Vol 83 (3) ◽  
pp. 295-313 ◽  
Author(s):  
Adelheid Degelmann ◽  
Cornelis P. Hollenberg
Keyword(s):  
Structural Analysis ◽  
Dna Sequences ◽  
Chironomus Tentans ◽  
Balbiani Ring

Microinjection of anti-topoisomerase I immunoglobulin G into nuclei of Chironomus tentans salivary gland cells leads to blockage of transcription elongation

1987 ◽  
Vol 7 (12) ◽  
pp. 4308-4316
Author(s):  
E Egyházi ◽  
E Durban
Keyword(s):  
Salivary Gland ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Immunoglobulin G ◽  
Topoisomerase I ◽  
Chironomus Tentans ◽  
Balbiani Ring ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Transcriptional Process

Purified anti-topoisomerase I immunoglobulin G (IgG) was microinjected into nuclei of Chironomus tentans salivary gland cells, and the effect on DNA transcription was investigated. Synthesis of nucleolar preribosomal 38S RNA by RNA polymerase I and of chromosomal Balbiani ring RNA by RNA polymerase II was inhibited by about 80%. The inhibitory action of anti-topoisomerase I IgG could be reversed by the addition of exogenous topoisomerase I. Anti-topoisomerase I IgG had less effect on RNA polymerase II-promoted activity of other less efficiently transcribing heterogeneous nuclear RNA genes. The pattern of inhibition of growing nascent Balbiani ring chains indicated that the transcriptional process was interrupted at the level of chain elongation. The highly decondensed state of active Balbiani ring chromatin, however, remained unaffected after injection of topoisomerase I antibodies. These data are consistent with the interpretation that topoisomerase I is an essential component in the transcriptional process but not in the maintenance of the decondensed state of active chromatin.

scholarly journals Structural interaction between the nuclear pore complex and a specific translocating RNP particle.

1995 ◽  
Vol 129 (5) ◽  
pp. 1205-1216 ◽  
Author(s):  
H Mehlin ◽  
B Daneholt ◽  
U Skoglund
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Pore ◽  
Initial Contact ◽  
Chironomus Tentans ◽  
Central Channel ◽  
Balbiani Ring ◽  
Salivary Gland Cells ◽  
Larval Salivary Gland ◽  
Nuclear Ring ◽  
Precise Area

The transport of Balbiani ring (BR) premessenger RNP particles in the larval salivary gland cells of the dipteran Chironomus tentans can be followed using electron microscopy. A BR RNP particle consists of an RNP ribbon bent into a ringlike structure. Upon translocation through the nuclear pore complex (NPC), the ribbon is straightened and enters the central channel of the NPC with the 5' end of the transcript in the lead. The translocating ribbon is likely to interact with the central channel but, in addition, the remaining portion of the ribbon ring makes contact with the periphery of the NPC. To determine the nature of this latter interaction, we have now studied the connections between the RNP particle and the border of the NPC during different stages of translocation using electron microscope tomography. It was observed that the 3' terminal domain of the ribbon always touches the nuclear ring of the NPC, but the precise area of contact is variable. Sometimes also a region on the opposite side of the ribbon ring reaches the nuclear ring. The pattern of contacts could be correlated to the stage of translocation, and it was concluded that the particle-nuclear ring interactions reflect a rotation of the ribbon ring in front of the central channel, the rotation being secondary to the successive translocation of the ribbon through the channel. The particle's mode of interaction with the NPC suggests that the initial contact between the 5' end domain of the ribbon and the entrance to the central channel is probably crucial to accomplish the ordered translocation of the premessenger RNP particle through the NPC.

RNA Synthesis in a Balbiani Ring in Chironomus tentans

1970 ◽  
Vol 35 (0) ◽  
pp. 513-519 ◽  
Author(s):  
B. Daneholt ◽  
J.-E. Edstrom ◽  
E. Egyhazi ◽  
B. Lambert ◽  
U. Ringborg
Keyword(s):  
Rna Synthesis ◽  
Chironomus Tentans ◽  
Balbiani Ring

Balbiani ring 1 gene in Chironomus tentans

1992 ◽  
Vol 225 (2) ◽  
pp. 349-361 ◽  
Author(s):  
Gabrielle Paulsson ◽  
Christer Höög ◽  
Kerstin Bernholm ◽  
Lars Wieslander
Keyword(s):  
Chironomus Tentans ◽  
Balbiani Ring

The Balbiani ring and the polytene chromosomes of Drosophila bicornuta

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 64-67 ◽  
Author(s):  
P. Mavragani-Tsipidou ◽  
Z. G. Scouras ◽  
A. Natsiou-Voziki
Keyword(s):  
Salivary Gland ◽  
Larval Development ◽  
Banding Pattern ◽  
Polytene Chromosomes ◽  
Balbiani Ring

A study of the BR1 and of the most prominent puffs during larval development and after in vitro ecdysterone treatment, as well as of the banding pattern and inverted tandem chromosomal duplications of the salivary gland chromosomes of Drosophila bicornuta, is presented in this report. These data are compared and discussed with those of D. auraria and D. serrata, two other montium species.Key words: Drosophila, Balbiani ring, duplications, ecdysterone.

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