The gene encoding SMR1, a precursor-like polypeptide of the male rat submaxillary gland, has the same organization as the preprothyrotropin-releasing hormone gene.

SMR1 is a precursor-like polypeptide of the submaxillary glands of rats. Sequence analysis predicts that it could be processed by maturation enzymes to release a small peptide resembling the thyrotropin-releasing hormone. The SMR1 gene was isolated from a rat genomic library and sequenced. The SMR1 gene spans 4.7 kb and consists of three exons. The two introns occur a few nucleotides before the initiation codon in the 5' untranslated region, and a few nucleotides before the first predicted processing site, respectively. Such a structure is reminiscent of that of the preprothyrotropin-releasing hormone gene. The site of transcriptional initiation of the SMR1 gene was determined and 1.4 kb of 5'-flanking sequence was sequenced. The sequence analysis revealed the presence of alternating purine-pyrimidine tracts and of purine-rich sequences. In addition, some sequences which could be involved in the regulation of SMR1 gene expression were identified.