The thyroglobulin gene: evolutionary and regulatory issues.

The coding information for thyroglobulin synthesis is contained in a large transcription unit, which is made from the juxtaposition of short repetitive gene modules and of a copy of an ancient acetylcholinesterase homologue. Minor alternatively spliced transcripts with conservation of the reading frame seem to be common. Whether they have a role or represent noise in the splicing phenomena is unknown. Transcription of the thyroglobulin gene is controlled by cAMP through a pathway involving sequence motifs and trans-acting factors that differ from those identified so far in other systems.