Consists of a 7.9kb PstI/SalI genomic fragment including the hrg gene, with 0.9kb upstream of the 5'-most transcription start and 1.1kb downstream of the 3'-most poly(A) site.
The addition of hrg+7.9 to hrgPAP45 or hrgPAP21 animals rescues lethality, though only 20% and 5% (respectively) of the expected rescued progeny survive to adulthood.