Expression of novel splice variants of the G protein subunit, Go alpha, is tissue-specific and age-dependent in the rat.
Heterotrimeric G proteins play an essential role in coupling numerous surface membrane receptors to intracellular signal transduction pathways. Relatively little is known about the splice variants of G proteins, including whether they undergo differential expression as a function of aging. We screened for splice variants of the alpha subunit of the dominant inhibitory G protein family member G(o) in a variety of tissues from rat and examined the expression of these splice variants during development. The splice variants were characterized using specific primers for G(o)alpha1 and G(o)alpha2 in conjunction with reverse transcription-polymerase chain reaction, and subsequently sequenced. G(o)alpha1 expression dominated over G(o)alpha2 in all neuronal tissues screened, including cerebral cortex, pituitary, spinal cord, colon myenteric plexus, dorsal root ganglion, and prenatal cortex. The sequence data of G(o)alpha1 supports the presence of three splice variants: G(o)alpha1a, G(o)alpha1b, G(o)alpha1c. The G(o)alpha1a variant was reported previously [J. Biol. Chem. 262 (1987) 14241], whereas G(o)alpha1b and G(o)alpha1c represent novel variants. The G(o)alpha1b splice variant demonstrates a 94 bp deletion using a cryptic donor site in exon 10. The G(o)alpha1c variant demonstrates a complete deletion of exon 10. A protein product with a molecular weight of approximately 34 kDa consistent with that expected for G(o)alpha1c was identified using Western blot analysis and two-dimensional gel electrophoresis. The expression of G(o)alpha1a decreased postnatally, supporting a potential physiological role during fetal development, whereas G(o)alpha1c expression increased postnatally. The age-dependent and tissue-specific expression of the G(o)alpha1 splice variants presage a broader functional role than has been observed historically with G(o).
Yoo
Jong Hyeon
JH
Department of Internal Medicine, Gastrointestinal Peptide Research Center, University of Michigan, Ann Arbor 48109-0368, USA.
Yang
Young-Sang
YS
Choi
Ilkuen
I
Shangguan
Yu
Y
Song
Il
I
Neubig
Richard R
RR
Wiley
John W
JW
D000375:Aging / Q000502:physiology; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D008297:Male; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D020033:Protein Isoforms; D021122:Protein Subunits; D012333:RNA, Messenger; D019204:GTP-Binding Proteins