We have determined the nucleotide sequence of the murine immunoglobulin gamma 2a 
membrane 3' untranslated region (1413 nucleotides) and approximately 679 
nucleotides of downstream sequence. Two AATAAA hexanucleotide sequences are 
present in the 2092 nucleotide interval. The first one functions as the major 
polyA signal, directing cleavage and polyadenylation at a site 20 nucleotides 
downstream. Within 41 nucleotides downstream of the major membrane polyA signal 
are two sequences with 75% homology to the consensus sequence, 
(C/T)GTGTT(C/T)(C/T), identified by McLauchlan et al. [Nucl. Acids Res. 13, 
1347-1365 (1985)]. An 80% homology match to the Berget consensus sequence, 
CA(C/T)TG, begins five nucleotides 3' of the major polyA site (used 20 times 
more than the second, downstream polyA site) [Berget Nature 309, 179-182 
(1984)]. The second AATAAA, located 73 nucleotides 3' of the first, directs 
cleavage and polyadenylation 18 nucleotides downstream at a minor polyA site. 
One match with 75% homology to the McLauchlan consensus sequence begins 17 
nucleotides 3' of the second (weaker) polyA site. No matches to the Berget 
consensus sequence are located near this second, weaker polyA site.