Regulation of SP60 mRNA during development of Dictyostelium discoideum.

The accumulation of mRNA recognized by oligonucleotides coding for a portion of the spore coat protein, SP60, was determined throughout development of Dictyostelium discoideum. The 1.8 kb mRNA first appears at the tipped aggregate stage and accumulates until culmination. This mRNA is present in pre-spore cells but absent from pre-stalk cells. A cDNA clone was selected by the oligonucleotides and found to be homologous to this mRNA. Although the oligonucleotides were designed to match the sequence coding for a hexapeptide repeat at the amino-terminus of SP60, they were able to recognize a similar repeated region at the carboxy-terminus of the protein coded by the cDNA clone. The SP60 gene appears to be subject to temporal and cell-type-specific transcriptional controls that are coordinate with those of SP96, another spore coat gene.