La. Elenich et al., THE GAMMA-1 HEAVY-CHAIN GENE INCLUDES ALL OF THE CIS-ACTING ELEMENTS NECESSARY FOR EXPRESSION OF PROPERLY REGULATED GERM-LINE TRANSCRIPTS, The Journal of immunology, 157(1), 1996, pp. 176-182
The regulation of heavy chain switch recombination and the production
of germ-line transcripts are highly correlated. IL-4 induces the produ
ction of murine gamma 1 germ-line transcripts, and much, if not all, o
f the regulation is transcriptional. We have investigated the cis-acti
ng elements involved in the regulation of expression of germ-line tran
scripts by preparing transgenes with the gamma 1 locus. A construct th
at includes 5' flanking regions, I gamma 1, S gamma 1, and C gamma 1,
is regulated like the endogenous gene. Deletion of either most of S ga
mma 1 or most of C gamma 1 does not alter the correctly regulated expr
ession of the transgenes. An element common to these three different g
amma 1 transgenes confers insertion-site independence and copy-number
dependence on the transgenes. Finally, the absolute amount of gamma 1
germ-line transcripts is regulated, as transgenic mice with more than
30 gamma 1 genes express no more germ-line transcripts than nontransge
nic mice.