May play a role in growth regulation and in negative regulation of cell cycle progression. Primarily found in the cytoplasm. A minor portion can be detected in some cells in the nucleus. Highest levels in intestine. Intermediate levels in spleen, brain and kidney. Low levels in testis, stomach, pancreas, liver, salivary gland and muscle. According to PubMed:9139721 also abundant in thymus. Expression levels oscillate moderately through the cell cycle. Activated in B-cells by agents causing growth inhibition or growth arrest. Belongs to the cyclin family. Cyclin G subfamily.