 GM-CSF also plays a role in embryonic development by functioning as an embryokine produced by reproductive tract.The human gene has been localized in close proximity to the interleukin 3 gene within a T helper type 2-associated cytokine gene cluster at chromosome region 5q31, which is known to be associated with interstitial deletions in the 5q- syndrome and acute myelogenous leukemia.GM-CSF and IL-3 are separated by an insulator element and thus independently regulated.