Arpp, a new homolog of carp, is preferentially expressed in type 1 skeletal muscle fibers and is markedly induced by denervation.
In this study, we isolated and characterized a murine counterpart of the human Arpp (hArpp) gene. Sequence analysis revealed that the murine Arpp (mArpp) gene is almost identical to the Ankrd2 gene, which has recently been isolated as a mouse gene induced in stretched skeletal muscle. The mArpp gene encodes a protein of 332 amino acids that contains four well-conserved ankyrin-repeat domains in the central portion of the protein. The amino acid sequence of mArpp protein (mArpp) is highly homologous to that of mouse cardiac-restricted ankyrin-repeat protein (Carp), which is proposed to be a putative genetic marker for cardiac hypertrophy. Immunohistochemical analysis revealed that mArpp is preferentially expressed in type 1 skeletal muscle fibers, and that mArpp is localized in both the nucleus and the sarcomeric I-band of muscle fibers, suggesting that Arpp may function as a nuclear and sarcomeric protein. Furthermore, mArpp was also expressed in neurons of the cerebellum and cerebrum, the islets of Langerhans in the pancreas, and the esophageal epithelium, suggesting that mArpp may play a functional physiologic role in brain, pancreas, and esophagus as well as in type 1 muscle fibers. Interestingly, although mArpp was localized in both nucleus and cytoplasm in neurons, its localization was restricted to nucleus in pancreas and esophagus, suggesting that intracellular localization of mArpp is regulated in a tissue-specific manner. Furthermore, we found that mArpp- and Carp-expression in skeletal muscle were markedly up-regulated after denervation. Although the elevated expression level of Carp was kept only for two weeks after denervation, that of Arpp was kept at least for 4 weeks, suggesting that mArpp and Carp may play distinct functional roles in denervated skeletal muscle.
Tsukamoto
Yoshiyuki
Y
Department of Molecular Biology, Faculty of Medicine, Tottori University, Yonago, Japan.
Senda
Takao
T
Nakano
Toshiya
T
Nakada
Chisato
C
Hida
Takehiko
T
Ishiguro
Naoko
N
Kondo
Gento
G
Baba
Takeshi
T
Sato
Kenzo
K
Osaki
Mitsuhiko
M
Mori
Shigeo
S
Ito
Hisao
H
Moriyama
Masatsugu
M
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D007124:Immunoenzyme Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009121:Muscle Denervation; D018657:Muscle Fibers, Slow-Twitch / Q000737:chemistry / Q000378:metabolism*; D009124:Muscle Proteins; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D012097:Repressor Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
C432364:ANKRD2 protein, human; D018076:DNA, Complementary; D009124:Muscle Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins