Regulation of quiescence in lymphocytes.

Cellular quiescence is a state characterized by decreased cell size and metabolic activity. In quiescent nai;ve lymphocytes, antigen recognition with appropriate co-stimulation triggers exit from G0 phase of the cell cycle, increased size and metabolism and progression through the cell cycle. Recent studies have shown that quiescence in lymphocytes is an actively maintained state rather than a default pathway in the absence of signal. Certain transcription factors appear to act as master regulators of gene expression patterns that enforce the quiescent phenotype. Here, we discuss candidate lymphocyte quiescence factors and their potential target genes and mechanisms of action.