thumb|right|alt=image of four oval-shaped blue nuclei containing small green dots representing cajal bodies. |nuclei of mouse cells (blue) containing cajal bodies (green) visualized by fusion of p80/coilin protein to gfp. cajal bodies (cbs) are spherical sub-organelles of 0.3-1.0&nbsp;Âµm in diameter found in the nucleus of proliferative cells like embryonic cells and tumor cells, or metabolically active cells like neurons. in contrast to cytoplasmic organelles, cbs lack any phospholipid membrane which would separate their content, largely consisting of proteins and rna, from the surrounding nucleoplasm. they were first reported by santiago ramÃ³n y cajal in 1903, who called them nucleolar accessory bodies due to their association with the nucleoli in neuronal cells. they were rediscovered by electron microscopists and named coiled bodies, according to their appearance as coiled threads on em images, and later renamed after their discoverer. research on cbs was accelerated after discovery and cloning of the marker protein p80/coilin. cbs have been implicated in rna-related metabolic processes such as snrnps biogenesis, maturation and recycling, histone mrna processing and telomere maintenance. cbs assemble rna which is used by telomerase to add nucleotides to the ends of telomeres. ==history== cbs were initially discov
Cell_anatomy Cell_nucleus Nuclear_substructures Organelles Telomeres