Medical research

How a microRNA protects vascular integrity

Short RNA molecules known as microRNAs (miRNAs) play a vital role in the regulation of gene expression. Anomalies in miRNAs expression and function have been implicated in pathological processes, such as the development of ...

Medical research

The difference between physical and psychosocial stress

A sports stress test and psychosocial stress produce similar stress hormone increases. And yet, the first one is perceived as positive, the second one as negative. Researchers attempt to find out why.

Genetics

A deep dive into cellular aging

Scientists at Sanford Burnham Prebys Medical Discovery Institute and Harvard University have discovered that mitochondria trigger senescence, the sleep-like state of aged cells, through communication with the cell's nucleus—and ...

Oncology & Cancer

Disorderly DNA helps cancer cells evade treatment

Each cell in the human body holds a full two meters of DNA. In order for that DNA to fit into the cell nucleus—a cozy space just one hundredth of a millimeter of space—it needs to be packed extremely tight.

Oncology & Cancer

Researchers identify new therapeutic target for colorectal cancer

Researchers at the University of Toronto have identified a key protein that supports the growth of many colorectal cancers. The study, which will be published December 27 in the Journal of Cell Biology, reveals that a protein ...

Oncology & Cancer

New principle for activation of cancer genes discovered

Researchers have long known that some genes can cause cancer when overactive, but exactly what happens inside the cell nucleus when the cancer grows has so far remained enigmatic. Now, researchers at Karolinska Institutet ...

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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.

This text uses material from Wikipedia, licensed under CC BY-SA