Jun Ohsumi

Molecular cloning of cDNA encoding adipogenesis inhibitory factor and identity with interleukin‐11

A cDNA encoding a novel adipogenesis inhibitory factor (AGIF) that inhibits the process of adipogenesis in mouse 3T3‐L1 preadipocytes was cloned from a cDNA library of the human bone marrow‐derived stromal cell line KM‐102. The cloned cDNA contains an open reading frame coding for an AGIF precursor of 199 amino acids. Analysis of the sequence of this cDNA revealed identity of this factor with a recently reported novel cytokine, designated interleukin‐11 (IL‐11). AGIF/IL‐11 may play an important role in stromal cell‐associated hematopoiesis through its regulatory action on adipocyte differentiation in the bone marrow microenvironment.

Adipogenesis inhibitory factor A novel inhibitory regulator of adipose conversion in bone marrow

Recombinant adipogenesis inhibitory factor (AGIF) was purified to homogeneity from the conditioned medium of COS‐1 cells transfected with human AGIF cDNA. The amino‐terminal sequence analysis of the mature AGIF revealed that AGIF was produced as a precursor consisting of 199 amino acids and processed into a mature form of 178 amino acids by a cleavage between Ala(−1) and Pro(+1). The purified AGIF inhibited the process of adipogenesis in mouse 3T3‐L1 preadipocytes, indicating that AGIF directly acts on the cells. AGIF acted as an adipogenic antagonist not only on the extramedullary cell line 3T3‐L1 but also on the mouse bone marrow stroma‐derived cell line H‐I/A, suggesting that this cytokine may regulate adipogenesis in bone marrow.