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Molecular cloning and sequence determination of four different cDNA species coding for α‐subunits of G proteins from Xenopus laevis oocytes
Author(s) -
Olate Juan,
Martinez Sixta,
Purcell Patricia,
Jorquera Hugo,
Codina Juan,
Bimbaumer Lutz,
Allende Jorge E.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80964-k
Subject(s) - xenopus , complementary dna , biology , amino acid , open reading frame , coding region , microbiology and biotechnology , gene , protein subunit , peptide sequence , serine , molecular cloning , cdna library , oligonucleotide , cloning (programming) , biochemistry , genetics , phosphorylation , computer science , programming language
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 NH 2 , 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.