Molecular cloning and expression of mouse mg(2+)-dependent protein phosphatase beta-4 (type 2C beta-4).
A full-length complementary DNA (cDNA) clone (pTK-3) encoding an isoform of Mg(2+)-dependent protein phosphatase beta (MPP beta-4) was isolated for the first time from a mouse melanocyte cDNA library. It was strongly suggested that the mRNA corresponding to the pTK-3 insert was a splicing variant of a single pre-mRNA that also encodes MPP beta-1 and -2 (T. Terasawa, T. Kobayashi, T. Murakami, M. Ohnishi, S. Kato, O. Tanaka, H. Kondo, H. Yamamoto, T. Takeuchi, and S. Tamura, 1993, Arch. Biochem. Biophys. 307, 342-349). The amino acid sequence of MPP beta-4 differed from those of MPP beta-1 and -2 only at the carboxyl terminal region. Analysis by reverse transcriptase polymerase chain reaction (RT-PCR) revealed that MPP beta-4 mRNA was expressed only in testis and intestine and not in other mouse tissues tested. Specific expression of the mRNA signals of two other isoforms of MPP beta, MPP beta-3 and -5 (a novel isoform), in testis and intestine was also demonstrated by the RT-PCR. The carboxyl terminal region of MPP beta-5 was found to have a chimera structure composed of part of MPP beta-1 and part of MPP beta-3. The recombinant MPP beta-3 and -4 and the putative MPP beta-5 expressed in Escherichia coli cells exhibited Mg(2+)-dependent and okadaic acid-insensitive protein phosphatase activities. It was demonstrated that the mRNA expression levels of MPP beta-3, -4, and -5 alter according to the maturation of mouse testis. These results suggest that the complex structure of MPP beta isoforms and their tissue- and developmental stage-specific expression reflect the variety of their physiological functions.
Kato
S
S
Department of Biochemistry, Tohoku University, Sendai, Japan.
Terasawa
T
T
Kobayashi
T
T
Ohnishi
M
M
Sasahara
Y
Y
Kusuda
K
K
Yanagawa
Y
Y
Hiraga
A
A
Matsui
Y
Y
Tamura
S
S
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D015870:Gene Expression; D015723:Gene Library; D014644:Genetic Variation; D008544:Melanocytes / Q000201:enzymology; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010749:Phosphoprotein Phosphatases / Q000096:biosynthesis* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D000071636:Protein Phosphatase 2C; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D015183:Restriction Mapping
D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D011994:Recombinant Proteins; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C