Cloning and sequencing of the gene for Tetrahymena calcium-binding 25-kDa protein (TCBP-25).
With the intention of studying calcium-dependent ciliary reversal in Tetrahymena, we isolated a Tetrahymena calcium-binding protein of 10 kDa (TCBP-10) which was not calmodulin and reported its properties (Ohnishi, K., and Watanabe, Y. (1983) J. Biol. Chem. 258, 13978-13985). However, immunoblotting with an antiserum against TCBP-10 and sequencing of the cDNAs and partial genomic DNAs for this calcium-binding protein prove that this previously reported TCBP-10 is the degraded product of a 25-kDa calcium-binding protein. Thus, we correct the name of the protein from TCBP-10 to TCBP-25. From the analysis of the cDNA for TCBP-25, it is shown to be composed of 218 amino acid residues and its molecular weight is estimated to be 24,702. This protein is predicted to contain four EF-hand-type calcium binding domains and to be a member of the calmodulin family. Little sequence homology with other proteins was shown by a computer search, except in the EF-hand regions. The special feature of TCBP-25 is that the distance between calcium-binding domains II and III is extraordinarily long for a calmodulin family protein having four calcium-binding domains. The genomic DNA for TCBP-25 contains two introns situated at short distances before calcium-binding domains I and III, implying gene duplication in genealogy.
Takemasa
T
T
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Ohnishi
K
K
Kobayashi
T
T
Takagi
T
T
Konishi
K
K
Watanabe
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005796:Genes; D015151:Immunoblotting; D008969:Molecular Sequence Data; D008970:Molecular Weight; D015345:Oligonucleotide Probes; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013768:Tetrahymena / Q000235:genetics*
D002135:Calcium-Binding Proteins; D015345:Oligonucleotide Probes; D004247:DNA