Cajal bodies: the first 100 years.
Cajal bodies are small nuclear organelles first described nearly 100 years ago by Ramón y Cajal in vertebrate neural tissues. They have since been found in a variety of animal and plant nuclei, suggesting that they are involved in basic cellular processes. Cajal bodies contain a marker protein of unknown function, p80-coilin, and many components involved in transcription and processing of nuclear RNAs. Among these are the three eukaryotic RNA polymerases and factors required for transcribing and processing their respective nuclear transcripts: mRNA, rRNA, and pol III transcripts. A model is discussed in which Cajal bodies are the sites for preassembly of transcriptosomes, unitary particles involved in transcription and processing of RNA. A parallel is drawn to the nucleolus and the preassembly of ribosomes, which are unitary particles involved in translation of proteins.
Gall
J G
JG
Department of Embryology, Carnegie Institution, Baltimore, Maryland 21210, USA. gall@ciwemb.edu.
D020413:3' Untranslated Regions / Q000378:metabolism; D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D006657:Histones; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D009865:Oocytes / Q000378:metabolism; D015388:Organelles / Q000378:metabolism / Q000502:physiology*; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional
D020413:3' Untranslated Regions; D006657:Histones; D009687:Nuclear Proteins; D012322:RNA Precursors; C068921:p80-coilin