Organizacja i funkcja ciałek Cajala

There is much interest in recent years in the possible role of different nuclear bodies (NBs) in cellular functions. NBs include the well-characterized Cajal bodies (CBs; or coiled bodies), which were first described in vertebrate neurons by Ramón y Cajal nearly 100 years ago and since then demonstrated in a variety of organisms and cell types, including both animals and plants. Cajal bodies contain C snurposomes with their associated B snurposomes. Many discussions of CB function emphasize their possible involvement in assembly, modification, or storage of RNA processing factors, especially small nucleolar ribonucleoprotein particles (snoRNPs), splicing small nuclear ribonucleoprotein particles (snRNPs), and the U7 snRNP. Moreover, some evidence suggests that CBs play an even wider role in transcription. Taking into account the composition of CBs and the targeting of various transcription and processing factors to CBs, we conclude that theymay be the primary site for assembly of the transcription machinery of the nucleus. The objective of this article is to summarize some aspects of these nuclear bodies, including their proposed roles in cells and in human diseases.