Cell nucleus
hideIn cell biology, the nucleus (pl. nuclei; from Latin nucleus or nuculeus, or kernel), also sometimes referred to as the "control center", is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome. The function of the nucleus is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression--the nucleus is therefore the control center of the cell.
The main structures making up the nucleus are the nuclear envelope, a double membrane that encloses the entire organelle and separates its contents from the cellular cytoplasm, and the nuclear lamina, a meshwork within the nucleus that adds mechanical support, much like the cytoskeleton supports the cell as a whole. Because the nuclear membrane is impermeable to most molecules, nuclear pores are required to allow movement of molecules across the envelope. These pores cross both of the membranes, providing a channel that allows free movement of small molecules and ions. The movement of larger molecules such as proteins is carefully controlled, and requires active transport regulated by carrier proteins. Nuclear transport is crucial to cell function, as movement through the pores is required for both gene expression and chromosomal maintenance.
Although the interior of the nucleus does not contain any membrane-bound subcompartments, its contents are not uniform, and a number of subnuclear bodies exist, made up of unique proteins, RNA molecules, and particular parts of the chromosomes. The best known of these is the nucleolus, which is mainly involved in the assembly of ribosomes. After being produced in the nucleolus, ribosomes are exported to the cytoplasm where they translate mRNA.
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News tagged with cell nuclei
Cells are like robust computational systems
Jun 16, 2009 |
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Gene regulatory networks in cell nuclei are similar to cloud computing networks, such as Google or Yahoo!, researchers report today in the online journal Molecular Systems Biology. The similarity is that each system keeps ...
Extreme makeover: Scientists explore new way to change cell's identity
May 05, 2009 |
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Even cells aren't immune to peer pressure. Scientists at the Stanford University School of Medicine have now shown that skin cells can be coaxed to behave like muscle cells -- and muscle cells like skin cells -- solely by ...
A secret to night vision found in DNA's unconventional 'architecture'
Apr 16, 2009 |
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Researchers have discovered an important element for making night vision possible in nocturnal mammals: the DNA within the photoreceptor rod cells responsible for low light vision is packaged in a very unconventional way, ...
Researchers 'unzip' molecules to measure interactions keeping DNA packed in cells
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Jan 28, 2009 |
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(PhysOrg.com) -- Anyone who has ever battled a stuck zipper knows it's a good idea to see what's stuck, where and how badly -- and then to pull hard. A Cornell research team's experiments involve the "unzipping" ...
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Lamin A/C deficiency is 'unnerving'
Biology /
Jan 05, 2009 |
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Mutations in the nuclear intermediate filament lamin A/C (LMNA) gene are associated with Emery-Dreifuss muscular dystrophy, but cause the disease by unknown mechanisms. Méjat et al. show that one mechanism ...
Stanford scientists turn adult skin cells into muscle and vice versa
Apr 30, 2009 |
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In a study featured on the cover of the May issue of The FASEB Journal, researchers describe how they are able to reprogram human adult skin cells into other cell types in order to decipher the elusive mechanisms underlying reprog ...
How red blood cells nuke their nuclei
Biology /
Feb 10, 2008 |
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Unlike the rest of the cells in your body, your red blood cells lack nuclei. That quirk dates back to the time when mammals began to evolve. Other vertebrates such as fish, reptiles, and birds, have red cells that contain ...
Active mechanism locks in the size of a cell's nucleus
Biology /
Dec 24, 2007 |
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Cells know that size matters, especially when it comes to the nucleus. In the early 1900s, German scientists first proposed that the size of a nucleus is always proportional to the size of its cell. Now, more than a century ...
Plant Scientists Develop New Cell-Sorting Technique
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Jun 04, 2008 |
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A new cell-sorting technique developed by University of Arizona plant scientists has the potential to enhance our understanding of how cells of all types work – or, in the case of diseases such as cancer, how they fail to ...
Stem cell nuclei are soft 'hard drives,' study finds
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Oct 11, 2007 |
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Biophysicists at the University of Pennsylvania have discovered that the nuclei of human stem cells are particularly soft and flexible, rather than hard, making it easier for stem cells to migrate through ...
New insight into factors that drive muscle-building stem cells
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Jan 08, 2008 |
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A report in the January issue of Cell Metabolism, a publication of Cell Press, provides new evidence explaining how stem cells known as satellite cells contribute to building muscles up in response to exercise. These findin ...
Better MRI scans of cancers made possible
Jan 13, 2009 |
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Researcher Kristina Djanashvili has developed a substance that enables doctors to get better MRI scans of tumours. On Tuesday 13 January, Djanashvili will be soon awarded a doctorate by TU Delft, Netherlands, for her work ...
Scientists create new cloning method
Oct 04, 2006 |
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U.S. scientists say they have achieved a one-step somatic cell nuclear transfer procedure using a differentiated cell as a nuclear donor.
A beneficial suicide
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Jan 10, 2007 |
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They are the largest group of white blood cells: neutrophil granulocytes kill microorganisms. Neutrophils catch microbes with extracellular structures nicknamed Neutrophil Extracellular Traps (NETs) that are ...
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