Le. Iverson et al., TISSUE-SPECIFIC ALTERNATIVE SPLICING OF SHAKER POTASSIUM CHANNEL TRANSCRIPTS RESULTS FROM DISTINCT MODES OF REGULATING 3'-SPLICE CHOICE, Journal of neurobiology, 32(5), 1997, pp. 457-468
Alternative splicing of precursor RNA enables a single gene to encode
multiple protein isoforms with different functional characteristics an
d tissue distributions. Differential splicing of Drosophila Shaker (Sh
) gene transcripts regulates the tissue-specific expression of kinetic
ally distinct potassium ion channels throughout development. Regulatio
n of Sh alternative splicing is being examined in germline transforman
ts using lacZ as a reporter gene. P-element constructs were generated
in which one or both of the two mutually exclusive Sh 3' acceptor site
s were positioned in the same translational reading frame as the lacZ
coding sequences. The constructs were introduced into the germline and
the transgenic animals examined for tissue-specific beta-galactosidas
e expression patterns. Some tissues exhibit ''promiscuous'' splicing;
these tissues are competent to splice to either 3' acceptor even when
both are present on the same pre-mRNA. In other tissues splice choice
results from competition between the two 3' sites; these tissues can s
plice to either site when it is the only available 3' acceptor, but wh
en given a choice will splice to only one of the two 3' accepters. In
some tissues, splicing occurs exclusively at only one of the 3' accept
or sites; these tissues are not competent to splice to one of the site
s even if it is the only 3' acceptor present on the pre-mRNA. These re
sults suggests that multiple, distinct regulatory modes are operating
to control tissue-specific alternative splicing of Sh 3' domains and a
re discussed in terms of potential underlying mechanisms for regulatin
g the tissue-specific expression of alternatively spliced genes. (C) 1
997 John Wiley & Sons, Inc.