- Nuclear envelope
A nuclear envelope (NE) (also known as the perinuclear envelope, nuclear membrane, nucleolemma or karyotheca) is a double lipid bilayer that encloses the genetic material in eukaryotic cells. The nuclear envelope also serves as the physical barrier, separating the contents of the nucleus (DNA in particular) from the cytosol (cytoplasm). Many nuclear pores are inserted in the nuclear envelope, which facilitate and regulate the exchange of materials (proteins such as transcription factors, and RNA) between the nucleus and the cytoplasm.
Each of the two membranes is composed of a lipid bilayer. The outer membrane is continuous with the rough endoplasmic reticulum while the inner nuclear membrane is the primary residence of several inner nuclear membrane proteins. The outer and inner nuclear membrane are fused at the site of nuclear pore complexes. The structure of the membrane also consists of ribosomes.
The inner nuclear membrane is connected to the nuclear lamina, a network of intermediate filaments composed of various lamins (A, B1, B2, & C). The lamina acts as a site of attachment for chromosomes and provides structural stability to the nucleus. The lamins have been associated with various genetic disorders collectively termed laminopathies.
The space between the two membranes that make up the nuclear envelope is called the perinuclear space (also called the perinuclear cisterna, NE Lumen), and is usually about 20 - 40 nm wide.
The nuclear envelope has been postulated to play a role in the organization and transcriptional activity of chromatin.
- Histology at BU 20102loa
- Animations of nuclear pores and transport through the nuclear envelope
- Illustrations of nuclear pores and transport through the nuclear envelope
- MeSH Nuclear+envelope
Structures of the cell membrane Membrane lipids Membrane protein locations Other Structures of the cell nucleus / nuclear protein Envelope (membrane)/
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Look at other dictionaries:
nuclear envelope — the structure enclosing the cell nucleus and separating it from the cytoplasm, consisting of two concentric lipid bilayers (the inner and outer membranes) separated by a 30 nm wide perinuclear space. The outer membrane is continuous with the… … Medical dictionary
nuclear envelope — branduolio apvalkalėlis statusas T sritis augalininkystė apibrėžtis Dviguba membrana, atskirianti ląstelės branduolį nuo citoplazmos. atitikmenys: angl. nuclear envelope rus. ядерная оболочка … Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas
nuclear envelope — Membrane system that surrounds the nucleus of eukaryotic cells. Consists of inner and outer membranes separated by perinuclear space and perforated by nuclear pores. The term should be used in preference to the term nuclear membrane which is… … Dictionary of molecular biology
nuclear envelope — noun see nuclear membrane … New Collegiate Dictionary
nuclear envelope — Double layered membrane separating the nucleoplasm from the cytoplasm; nuclear membrane … Dictionary of invertebrate zoology
nuclear envelope — (nu kle ar) The complex double membrane structure forming the outer boundary of the eucaryotic nucleus. It is covered by pores through which substances enter and leave the nucleus … Dictionary of microbiology
nuclear membrane — n a double membrane enclosing a cell nucleus and having its outer part continuous with the endoplasmic reticulum called also karyotheca * * * 1. either of the membranes, inner and outer, comprising the 2. nuclear envelope. nuclear envelope … Medical dictionary
nuclear membrane — n. the double layered membrane of the nucleus of a cell, separating the nucleoplasm from the cytoplasm, that is permeable to certain molecules, esp. DNA, RNA, and ATP: now often nuclear envelope … English World dictionary
Nuclear lamina — The nuclear lamina is a dense ( 30 to 100 nm thick) fibrillar network inside the nucleus of a eukaryotic cell. It is composed of intermediate filaments and membrane associated proteins. Besides providing mechanical support, the nuclear lamina… … Wikipedia
Nuclear pore — Diagram of human cell nucleus. Nuclear pore labeled at bottom left … Wikipedia