polynucleate

Polynucleate is an adjective used in cell biology to describe cells or organisms that contain more than one nucleus. The term is commonly used interchangeably with multinucleate, though polynucleate may emphasize the presence of multiple nuclei rather than the process of having them. Polynucleation can arise by different cellular mechanisms and occurs in diverse groups of organisms, including animals, fungi, and protists.

Two main mechanisms produce polynucleate cells: cell fusion, producing a syncytium in which multiple nuclei share a single cytoplasm, and nuclear division without accompanying cytokinesis, yielding a coenocyte or plasmodial structure where many nuclei exist within one cytoplasmic mass.

Examples of polynucleate cells include skeletal muscle fibers (myocytes), which are classic multinucleate cells formed by fusion of precursor myoblasts; osteoclasts, multinucleated bone-resorbing cells derived from monocyte precursors; and plasmodial slime molds such as Physarum, whose plasmodium is a large coenocytic mass with numerous nuclei. Some algae and fungi also exhibit coenocytic hyphae or thalli, such as certain Caulerpa species.

Functions and significance of polynucleation include enabling large cell size and high metabolic capacity by providing distributed genetic control and localized protein production within extensive cytoplasm. Regulation and intracellular transport can be more complex in polynucleate cells, and the absence of distinct cell boundaries influences signaling and development.

See also: multinucleate, syncytium, coenocyte, plasmodium.