The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes

Edward B. Mougey, Marina O'Reilly, Yvonne Osheim, Oscar L. Miller, Ann Beyer, Barbara Sollner-Webb

Research output: Contribution to journalArticle

Abstract

When spread chromatin is visualized by electron microscopy, active rRNA genes have a characteristic Christmas tree appearance: From a DNA "trunk" extend closely packed "branches" of nascent transcripts whose ends are decorated with terminal "balls." These terminal balls have been known for more than two decades, are shown in most biology textbooks, and are reported in hundreds of papers, yet their nature has remained elusive. Here, we show that a rRNA-processing signal in the 5′-external transcribed spacer (ETS) of the Xenopus laevis ribosomal primary transcript forms a large, processing-related complex with factors of the Xenopus oocyte, analogous to 5′ ETS processing complexes found in other vertebrate cell types. Using mutant rRNA genes, we find that the same rRNA residues are required for this biochemically defined complex formation and for terminal ball formation, analyzed electron microscopically after injection of these cloned genes into Xenopus oocytes. This, plus other presented evidence, implies that rRNA terminal balls in Xenopus, and by inference, also in the multitude of other species where they have been observed, are the ultrastructural visualization of an evolutionarily conserved 5′ ETS processing complex that forms on the nascent rRNA.

Original languageEnglish (US)
Pages (from-to)1609-1619
Number of pages11
JournalGenes & development
Volume7
Issue number8
StatePublished - 1993

Fingerprint

Xenopus
Chromatin
rRNA Genes
Oocytes
Textbooks
Xenopus laevis
Vertebrates
Electron Microscopy
Electrons
Injections
DNA
Genes

Keywords

  • Chromatin spreads
  • Eukaryotic rRNA transcription units
  • rRNA processing complex
  • Terminal balls
  • X. Laevis

ASJC Scopus subject areas

  • Developmental Biology
  • Genetics

Cite this

Mougey, E. B., O'Reilly, M., Osheim, Y., Miller, O. L., Beyer, A., & Sollner-Webb, B. (1993). The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes. Genes & development, 7(8), 1609-1619.

The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes. / Mougey, Edward B.; O'Reilly, Marina; Osheim, Yvonne; Miller, Oscar L.; Beyer, Ann; Sollner-Webb, Barbara.

In: Genes & development, Vol. 7, No. 8, 1993, p. 1609-1619.

Research output: Contribution to journalArticle

Mougey, EB, O'Reilly, M, Osheim, Y, Miller, OL, Beyer, A & Sollner-Webb, B 1993, 'The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes', Genes & development, vol. 7, no. 8, pp. 1609-1619.
Mougey, Edward B. ; O'Reilly, Marina ; Osheim, Yvonne ; Miller, Oscar L. ; Beyer, Ann ; Sollner-Webb, Barbara. / The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes. In: Genes & development. 1993 ; Vol. 7, No. 8. pp. 1609-1619.
@article{98986318925540c9b75ee17dee2d9357,
title = "The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes",
abstract = "When spread chromatin is visualized by electron microscopy, active rRNA genes have a characteristic Christmas tree appearance: From a DNA {"}trunk{"} extend closely packed {"}branches{"} of nascent transcripts whose ends are decorated with terminal {"}balls.{"} These terminal balls have been known for more than two decades, are shown in most biology textbooks, and are reported in hundreds of papers, yet their nature has remained elusive. Here, we show that a rRNA-processing signal in the 5′-external transcribed spacer (ETS) of the Xenopus laevis ribosomal primary transcript forms a large, processing-related complex with factors of the Xenopus oocyte, analogous to 5′ ETS processing complexes found in other vertebrate cell types. Using mutant rRNA genes, we find that the same rRNA residues are required for this biochemically defined complex formation and for terminal ball formation, analyzed electron microscopically after injection of these cloned genes into Xenopus oocytes. This, plus other presented evidence, implies that rRNA terminal balls in Xenopus, and by inference, also in the multitude of other species where they have been observed, are the ultrastructural visualization of an evolutionarily conserved 5′ ETS processing complex that forms on the nascent rRNA.",
keywords = "Chromatin spreads, Eukaryotic rRNA transcription units, rRNA processing complex, Terminal balls, X. Laevis",
author = "Mougey, {Edward B.} and Marina O'Reilly and Yvonne Osheim and Miller, {Oscar L.} and Ann Beyer and Barbara Sollner-Webb",
year = "1993",
language = "English (US)",
volume = "7",
pages = "1609--1619",
journal = "Genes and Development",
issn = "0890-9369",
publisher = "Cold Spring Harbor Laboratory Press",
number = "8",

}

TY - JOUR

T1 - The terminal balls characteristic of eukaryotic rRNA transcription units in chromatin spreads are rRNA processing complexes

AU - Mougey, Edward B.

AU - O'Reilly, Marina

AU - Osheim, Yvonne

AU - Miller, Oscar L.

AU - Beyer, Ann

AU - Sollner-Webb, Barbara

PY - 1993

Y1 - 1993

N2 - When spread chromatin is visualized by electron microscopy, active rRNA genes have a characteristic Christmas tree appearance: From a DNA "trunk" extend closely packed "branches" of nascent transcripts whose ends are decorated with terminal "balls." These terminal balls have been known for more than two decades, are shown in most biology textbooks, and are reported in hundreds of papers, yet their nature has remained elusive. Here, we show that a rRNA-processing signal in the 5′-external transcribed spacer (ETS) of the Xenopus laevis ribosomal primary transcript forms a large, processing-related complex with factors of the Xenopus oocyte, analogous to 5′ ETS processing complexes found in other vertebrate cell types. Using mutant rRNA genes, we find that the same rRNA residues are required for this biochemically defined complex formation and for terminal ball formation, analyzed electron microscopically after injection of these cloned genes into Xenopus oocytes. This, plus other presented evidence, implies that rRNA terminal balls in Xenopus, and by inference, also in the multitude of other species where they have been observed, are the ultrastructural visualization of an evolutionarily conserved 5′ ETS processing complex that forms on the nascent rRNA.

AB - When spread chromatin is visualized by electron microscopy, active rRNA genes have a characteristic Christmas tree appearance: From a DNA "trunk" extend closely packed "branches" of nascent transcripts whose ends are decorated with terminal "balls." These terminal balls have been known for more than two decades, are shown in most biology textbooks, and are reported in hundreds of papers, yet their nature has remained elusive. Here, we show that a rRNA-processing signal in the 5′-external transcribed spacer (ETS) of the Xenopus laevis ribosomal primary transcript forms a large, processing-related complex with factors of the Xenopus oocyte, analogous to 5′ ETS processing complexes found in other vertebrate cell types. Using mutant rRNA genes, we find that the same rRNA residues are required for this biochemically defined complex formation and for terminal ball formation, analyzed electron microscopically after injection of these cloned genes into Xenopus oocytes. This, plus other presented evidence, implies that rRNA terminal balls in Xenopus, and by inference, also in the multitude of other species where they have been observed, are the ultrastructural visualization of an evolutionarily conserved 5′ ETS processing complex that forms on the nascent rRNA.

KW - Chromatin spreads

KW - Eukaryotic rRNA transcription units

KW - rRNA processing complex

KW - Terminal balls

KW - X. Laevis

UR - http://www.scopus.com/inward/record.url?scp=0027259044&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027259044&partnerID=8YFLogxK

M3 - Article

C2 - 8339936

AN - SCOPUS:0027259044

VL - 7

SP - 1609

EP - 1619

JO - Genes and Development

JF - Genes and Development

SN - 0890-9369

IS - 8

ER -