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Two cell‐counting factors regulate the aggregate size of the cellular slime mold Dictyostelium discoideum

2001; Wiley; Volume: 43; Issue: 6 Linguagem: Inglês

10.1046/j.1440-169x.2001.00615.x

1440-169X

Takako Okuwa, Takahiro Katayama, Akinori Takano, Ken-Ichi Kodaira, Hiroo Yasukawa,

Skin and Cellular Biology Research

Countin, a cell‐counting factor in Dictyostelium discoideum , is considered to limit the maximum size of the multicellular structure, because a countin null strain forms a huge fruiting body compared to that of the wild‐type. A novel gene, countin2 , that is highly homologous to countin (40% identity in amino acid sequence) was identified in the D. discoideum genome. The countin2 null strain formed a 1.7‐fold higher number of the aggregates, resulting in smaller fruiting bodies compared with those of wild‐type cells. Thus, the Countin2 protein is thought to limit the minimum size of the multicellular structure. The size and number of aggregates formed by a mixture of countin null and countin2 null strains were the same as those of the wild‐type. These findings demonstrate that a combination of Countin and Countin2 proteins determines the appropriate size of the multicellular structure of D. discoideum .