Molecular cloning and sequence determination of four different cDNA species coding for α‐subunits of G proteins from Xenopus laevis oocytes

FEBS Letters

Martinez, Sixta³  Codina, Juan¹  Bimbaumer, Lutz¹  Jorquera, Hugo²  Olate, Juan²  Purcell, Patricia²  Allende, Jorge E.² 

[1]Department of Cell Biology, Baylor College of Medicine, Texas Medical Center, Houston, TX 77030, USA

[2]Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Casilla 70086, Santiago 7, Chile

[3]Departamento de Quimica, Universidad Nacional, Bogotá, Colombia

关键词: G-protein;    cDNA cloning;    Nucleotide sequence;    Xenopus laevis oocyte;   

DOI  :  10.1016/0014-5793(90)80964-K

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A cDNA library preprared from Xenopus laevis oocytes in λgt10 was screened with a mixture of three oligonucleotide probes designed to detect sequences found in different mammalian genes coding for a-subunits of G-proteins. In addition to a clone coding for a Gαo-type subunit previously reported [(1989) FEBS Lett. 244, 188-192] four additional clones have been found coding for different Gα protein subunits. By comparison with mammalian α-subunits, these oocyte cDNAs correspond to two closely related Gas-la, to a Gαi-1 and to a Gαi-3 species. The derived amino acid sequences showed that both Gαs species contain 379 residues, corresponding to the short species without the serine residue and with a calculated M _r of 42720. The Gαi-1 gene encodes a 354 amino acid protein with an M _r, of 39000 and the Gαi-3 encodes an incomplete open reading frame of 345 residues, lacking the first 9 amino acid residues at the NH₂, terminus. All these Gα-subunits showed high identity with their respective mammalian counterparts (75–80%), indicating a great degree of conservation through the evolution and the important cellular regulatory function that they play.

【 授权许可】

Unknown