Computational search for over-represented 8-mers within the 5′-regulatory regions of 634 mouse testis-specific genes

Accumulation of microarray data has enabled the computational analysis of gene expressions in various tissues. Although the genes showing testis-specific expression are most abundant among the genes exhibiting tissue-specific expression, no systematic study has been conducted for over-represented motifs within their regulatory regions. We have identified 117 over-represented 8-mers that appeared 2648 times within the regulatory regions of 634 testis-specific genes. Of these, 64 over-represented 8-mers were significantly more frequent in the regulatory regions of testis-specific genes than in those of non-testis-specific genes. In this group of 8-mers, 4 8-mers differed from the canonical cAMP response element (CRE) 8-mer by 1 letter, but the canonical CRE was not included in this group. We consider that CRE-like 8-mers participate in the regulatory expression of testis-specific genes to a greater extent than the canonical CRE 8-mer.