The structure and expression of a novel gene activated in early XXXX embryogenesis.

@entity19 @entity7007 @entity7728
We report the cloning and sequence determination of the @entity19 @entity7728 gene. This gene is under the genetic control of two trans-acting loci in the @entity19 , termed raf and Rif. These loci determine the adult basal and inducible levels, respectively, of @entity7728 mRNA, as well as the mRNA for @entity7007 . By elucidating the sequence and structure of the @entity7728 gene we show that it is unrelated to the @entity7007 gene, and therefore must have acquired its regulation by raf and Rif independently. The sequence also indicates that the @entity7728 gene has a very unusual structure. It is composed of five exons, 1307, 135, 119, 127 and 560 bp in size, along with four very small introns whose combined lengths are 270 bases. The largest open reading frame of the gene, sufficient to encode a protein of approximately 14 kd, is contained entirely within the first large exon, 680 bases downstream of the cap site of the mRNA. Preceding the translation initiation codon are four ATG codons, each of which is followed shortly thereafter by translation terminator codons. The rest of the gene, which encompasses all five exons, is presumed to be untranslated. That the long 5' untranslated region may be used to regulate the translation of the mRNA is suggested from in vitro translation studies. Experiments which utilized tissue culture cell lines of the mesodermal lineage suggest that the gene is activated very early during muscle cell differentiation.
