Study uncovers key step in cell protein production

Scientists at the University of Sheffield have discovered how genes create proteins in research which could aid the development of treatments for human diseases.

Nuclear membrane Lem2 necessary for nuclear scaling

A study led by Hiroshima University finds that nuclear membrane protein Lem2 acts as a valve to control the size of the nucleus, keeping it in proportion to the size of the cell

Innovative mechanobiology research expands understanding of cells

Researchers have developed a new technology that allows them to probe cell changes without disturbing the cell's physiology—a major advancement that helps scientists look more closely at cell changes to solve human health ...

Veritable powerhouses—even without DNA

Whether human beings or animals, plants or algae: the cells of most life forms contain special structures that are responsible for energy production. Referred to as mitochondria, they normally have their own genetic material, ...

Protein production efficiency can be predicted by gene sequence

Today, thousands of databases with biological data are publicly available. They include data on gene and protein sequences and detailed measurements of different cellular parameters, such as the exact quantities of all proteins ...

How HIV DNA is blocked from entering the cell nucleus

Multiple components of the nuclear pore complex and nuclear import machinery enable a protein called human myxovirus resistance 2 (MX2) to inhibit HIV-1 infection, according to a study published November 29 in the open-access ...

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Cell nucleus

In 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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