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The nuclear envelope refers to the double membrane of the nucleus that encloses genetic material in eukaryotic cells. It separates the contents of the nucleus ( DNA in particular) from the cytosol. The space between the two membranes that make up the nuclear envelope is called the perinuclear space, and is usually about 20 - 100 nm wide. The outer membrane is continuous with the rough endoplasmic reticulum.Numerous nuclear pores are present on the nuclear envelope to facilitate and regulate the exchange of materials (for example, proteins and mRNA) between the nucleus and the cytoplasm.
The inner membrane is erected upon the nuclear lamina, a network of intermediate filaments made of lamin. This network of filaments is essential for the disarrangement of the nuclear envelope into vesicles during mitosis or meiosis, and its posterior reassembly. When, during the cell cycleThe cell cycle is the cycle of events in a eukaryotic cell from one cell division to the next. It consists of interphase, mitosis, and usually cell division. The cell cycle is regulated by cyclins and cyclin-dependent kinases. Hartwell, R. Timothy Hunt, a, a certain cyclin-dependent kinase complexA cyclin-dependent kinase complex (abbreviated cdkc also called cyclin-CDK is a protein complex formed by the association of cyclin with cyclin-dependent kinase. These complexes are involved in regulation of the cell cycle. Classes There are three classes phosphorylates the laminins they undergo a conformational change that triggers the disassembly of the nuclear envelope. After the chromosome2) Centromere. The point where the two chromatids touch, and where the microtubules attach. 3) Short arm. 4) Long arm. A chromosome is, minimally, a very long, continuous piece of DNA, which contains many genes, regulatory elements and other intervening ns have migrated to each pole, dephosphorylation of laminins causes the nucleus to reassemble.
The nuclear envelope may also play a role in the disposition of chromatinChromatin is a complex of DNA and protein in eukaryotic cells. The nucleic acids are generally in the form of double-stranded DNA. The major proteins involved in chromatin are histone proteins. In a eukaryotic cell, nearly all DNA is found compacted in ch inside the nucleus.
Synonyms: karyotheca, nuclear membrane, nucleolemma, perinuclear envelope
