Nuclear substructures

thumb|Different representations of chromosomes thumb|Main parts of a condensed chromosome thumb|212x212px|Condensed chromosome (purple rod) inside a bone marrow erythrokaryocyte undergoing mitosis

thumb |292px |Nucleolus contained within the cell nucleus

thumb|358x358px|The major structures in DNA compaction: DNA, the [[nucleosome, the 11 nm beads on a string chromatin fibre and the metaphase chromosome.]]

membrane part of the nuclear envelope

thumb|300px|The protoplasmic material of the nucleus including the [[nucleolus labelled as nucleoplasm.]] The nucleoplasm, also known as karyoplasm, is the type of protoplasm that makes up the cell nucleus, the most prominent organelle of the eukaryotic cell. It is enclosed by the nuclear envelope, also known as the nuclear membrane. The nucleoplasm resembles the cytoplasm of a eukaryotic cell in that it is a gel-like substance found within a membrane, although the nucleoplasm only fills out the space in the nucleus and has its own unique functions. The nucleoplasm suspends structures within t

class of nuclear body enriched in small nuclear ribonucleoproteins

the dense fibrillar network lying on the inner side of the nuclear membrane

process of compacting DNA molecules

region of a chromosome where nucleoli form during interphase, and where genes encoding the largest rRNA precursor transcript are tandemly arrayed

right|thumb|200px|Image of chicken chromosomes featuring the many microchromosomes (appearing as dots). The arrows indicate a stained gene locus on homologous macrochromosomes.

frame|An overlay of a fluorescence micrograph (green) onto a DIC image of a HeLa cell expressing a Yellow fluorescent Protein fusion of Paraspeckle Protein 1 (PSP1): 1. cytoplasm; 2. nucleus; 3. nucleolus; 4. paraspeckles In cell biology, a paraspeckle is an irregularly shaped compartment of the cell, approximately 0.2-1 μm in size, found in the nucleus' interchromatin space. First documented in HeLa cells, where there are generally 10-30 per nucleus, Paraspeckles are now known to also exist in all human primary cells, transformed cell lines and tissue sections. Their name is derived from thei

extra-nucleolar nuclear domains, usually visualized by confocal microscopy and fluorescent antibodies to specific proteins