Editing Nucleolus (section)

== History ==
The nucleolus was identified by [[bright-field microscopy]] during the 1830s.<ref name="Pederson-2011">{{cite journal | vauthors = Pederson T | title = The nucleolus | journal = Cold Spring Harbor Perspectives in Biology | volume = 3 | issue = 3 | pages = a000638 | date = March 2011 | pmid = 21106648 | pmc = 3039934 | doi = 10.1101/cshperspect.a000638 }}</ref> [[Theodor Schwann]] in his 1839 treatise described that [[Matthias Jakob Schleiden|Schleiden]] had identified small corpuscles in nuclei, and named the structures "Kernkörperchen". In a 1947 translation of the work to English, the structure was named "nucleolus".<ref>{{Cite web |title=Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen / Von Th. Schwann. Mit vier Kupfertafeln. |url=https://wellcomecollection.org/works/bknnmj2k |access-date=2024-03-12 |website=Wellcome Collection |language=en}}</ref><ref>{{Cite book |last=Schwann |first=Theodor |url=https://www.biodiversitylibrary.org/bibliography/17276 |title=Microscopical researches into the accordance in the structure and growth of animals and plants |last2=Schwann |first2=Theodor |last3=Smith |first3=Henry |last4=Schleiden |first4=M. J. |date=1847 |publisher=Sydenham Society |location=London |pages=3}}</ref>

{{Blockquote|text=In addition to these peculiarities of the cytoblast, already made known by Brown and Meyen, Schleiden has discovered in its interior a small corpuscle (see plate I, fig. 1, 4,) which, in the fully-developed cytoblast, looks like a thick ring, or a thick-walled hollow globule. It appears, however, to present a different appearance in different cytoblasts. Sometimes only the external sharply-defined circle of this ring can be distinguished, with a dark point in the centre,—occasionally, and indeed most frequently, only a sharply circumscribed spot. In other instances this spot is very small, and sometimes cannot be recognized at all. As it will frequently be necessary to speak of this body in the following treatise, I will for brevity’s sake name it the “nucleolus,” (Kernkorperchen, ‘nucleus-corpuscle.”)|author=Theodor Schwann, translated by Henry Smith|title=Microscopical Researches Into the Accordance in the Structure and Growth of Animals and Plants|source=page 3}}

Little was known about the function of the nucleolus until 1964, when a study<ref name="Brown-1964">{{cite journal | vauthors = Brown DD, Gurdon JB | title = Absence of ribosomal rna synthesis in the anucleolate mutant of xenopus laevis | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 51 | issue =  1| pages = 139–46 | date = January 1964 | pmid = 14106673 | pmc = 300879 | doi = 10.1073/pnas.51.1.139 | bibcode = 1964PNAS...51..139B | doi-access = free }}</ref> of nucleoli by [[John Gurdon]] and [[Donald D. Brown|Donald Brown]] in the African clawed frog ''[[Xenopus laevis]]'' generated increased interest in its function and detailed structure. They found that 25% of the frog eggs had no nucleolus, and that such eggs were not capable of life. Half of the eggs had one nucleolus and 25% had two. They concluded that the nucleolus had a function necessary for life. In 1966, [[Max L. Birnstiel]] and collaborators showed via [[nucleic acid hybridization]] experiments that DNA within nucleoli codes for [[ribosomal RNA]].<ref name="Birnstiel-1966">{{cite journal | vauthors = Birnstiel ML, Wallace H, Sirlin JL, Fischberg M | title = Localization of the ribosomal DNA complements in the nucleolar organizer region of Xenopus laevis | journal = National Cancer Institute Monograph | volume = 23 | pages = 431–47 | date = December 1966 | pmid = 5963987 }}</ref><ref name="Wallace-1966">{{cite journal | vauthors = Wallace H, Birnstiel ML | title = Ribosomal cistrons and the nucleolar organizer | journal = Biochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis | volume = 114 | issue = 2 | pages = 296–310 | date = February 1966 | pmid = 5943882 | doi = 10.1016/0005-2787(66)90311-x }}</ref>