Structure, expression, and evolution of a @entity1457 gene locus in XXXX that is flanked by repetitive elements.

@entity2199 @entity2036 @entity535 @entity1457 @entity27766 @entity27765 @entity16473 @entity71002 @entity71001
A locus containing two hsp16 genes in @entity2199 has been characterized by DNA sequencing. Each gene encodes a 16-kDa polypeptide which is expressed following heat induction. The two genes, designated @entity16473 and @entity27766 , are arranged in divergent orientations, and each contains a single intron of 46 and 58 base pairs, respectively. Although both gene transcripts are spliced efficiently in vivo, @entity27766 corresponds to a previously isolated cDNA which contains an unspliced intron sequence. The 5'-noncoding regions of both genes contain TATA boxes preceded 18 or 19 @entity2036 upstream by a @entity1457 regulatory sequence. The 3'-noncoding regions contain polyadenylation signals (AATAAA) either downstream ( @entity16473 ) or immediately adjacent ( @entity27766 ) to a sequence capable of forming a hairpin. This pair of hsp16 genes is flanked by three copies of an approximately 200-bp dispersed repetitive element (two copies on one side and a single one on the other side of the locus) which occurs in at least 70 copies throughout the @entity2199 genome, and has been designated CeRep-16. Together with data described previously (Russnak, R. H., and Candido, E. P. M. (1985) Mol. Cell. Biol. 5, 1268-1278), the results presented here define a family of four distinct, related small @entity1457 protein genes. These are arranged in divergently transcribed pairs at two loci. The @entity27765 /41 genes code for one class of HSP16, 143- @entity535 residues long, while the @entity71001 genes encode the other class, which is 2 @entity535 residues longer. Thus each locus codes for the two major types of HSP16. The two loci differ in a number of respects, including the presence of a tandem inverted duplication of two @entity1457 protein genes at one locus, and of repetitive elements at the other. Sequence comparisons allow us to propose a scheme for the evolution of the four genes and reveal conserved features of noncoding regions which may be involved in the regulation of their transcription, RNA processing, or translation. Using locus-specific hybridization probes, we have found that the genes at locus @entity16473 /41 are expressed at levels approximately 20-40-fold higher than those at locus @entity71002 .
