The human alpha subunit glycoprotein hormone gene utilizes a unique CCAAT binding factor.

Placenta-specific expression of the gene encoding the α subunit of glycoprotein hormones involves the interaction of at least two different cis-acting elements: the upstream regulatory element which binds a placenta-specific trans-acting factor; and two tandem cAMP-response elements (CREs), which bind a ubiquitous protein (CRE-binding protein). To identify additional elements required for promoter activity, we used block replacement mutagenesis to produce a series of 10-base pair transversion mutations throughout the proximal promoter-regulatory region of the human α subunit gene