TY - JOUR
T1 - Alternative splicing and polyadenylation contribute to the generation of hERG1 C-terminal isoforms
AU - Gong, Qiuming
AU - Stump, Matthew R.
AU - Dunn, A. Russell
AU - Deng, Vivianne
AU - Zhou, Zhengfeng
PY - 2010/10/15
Y1 - 2010/10/15
N2 - The human ether-a-go-go-related gene 1 (hERG1) encodes the pore-forming subunit of the rapidly activating delayed rectifier potassium channel. Several hERG1 isoforms with different N- and C-terminal ends have been identified. The hERG1a, hERG1b, and hERG1-3.1 isoforms contain the full-length C terminus, whereas the hERG1USO isoforms, hERG1aUSO and hERG1b USO, lack most of the C-terminal domain and contain a unique C-terminal end. The mechanisms underlying the generation of hERG1USO isoforms are not understood. We show that hERG1 isoforms with different C-terminal ends are generated by alternative splicing and polyadenylation of hERG1 pre-mRNA. We identified an intrinsically weak, noncanonical poly(A) signal, AGUAAA, within intron 9 of hERG1 that modulates the expression of hERG1a and hERG1aUSO. Replacing AGUAAA with the strong, canonical poly(A) signal AAUAAA resulted in the predominant production of hERG1aUSO and a marked decrease in hERG1 current. In contrast, eliminating the intron 9 poly(A) signal or increasing the strength of 5′ splice site led to the predominant production of hERG1a and a significant increase in hERG1 current. We found significant variation in the relative abundance of hERG1 C-terminal isoforms in different human tissues. Taken together, these findings suggest that post-transcriptional regulation of hERG1 pre-mRNA may represent a novel mechanism to modulate the expression and function of hERG1 channels.
AB - The human ether-a-go-go-related gene 1 (hERG1) encodes the pore-forming subunit of the rapidly activating delayed rectifier potassium channel. Several hERG1 isoforms with different N- and C-terminal ends have been identified. The hERG1a, hERG1b, and hERG1-3.1 isoforms contain the full-length C terminus, whereas the hERG1USO isoforms, hERG1aUSO and hERG1b USO, lack most of the C-terminal domain and contain a unique C-terminal end. The mechanisms underlying the generation of hERG1USO isoforms are not understood. We show that hERG1 isoforms with different C-terminal ends are generated by alternative splicing and polyadenylation of hERG1 pre-mRNA. We identified an intrinsically weak, noncanonical poly(A) signal, AGUAAA, within intron 9 of hERG1 that modulates the expression of hERG1a and hERG1aUSO. Replacing AGUAAA with the strong, canonical poly(A) signal AAUAAA resulted in the predominant production of hERG1aUSO and a marked decrease in hERG1 current. In contrast, eliminating the intron 9 poly(A) signal or increasing the strength of 5′ splice site led to the predominant production of hERG1a and a significant increase in hERG1 current. We found significant variation in the relative abundance of hERG1 C-terminal isoforms in different human tissues. Taken together, these findings suggest that post-transcriptional regulation of hERG1 pre-mRNA may represent a novel mechanism to modulate the expression and function of hERG1 channels.
UR - http://www.scopus.com/inward/record.url?scp=77957806896&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77957806896&partnerID=8YFLogxK
U2 - 10.1074/jbc.M109.095695
DO - 10.1074/jbc.M109.095695
M3 - Article
C2 - 20693282
AN - SCOPUS:77957806896
SN - 0021-9258
VL - 285
SP - 32233
EP - 32241
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 42
ER -