Cloning and functional expression of a neuronal calcium channel beta subunit from house fly (Musca domestica).
The primary structure of a calcium channel beta subunit (beta M) from housefly (Musca domestica) has been deduced by cDNA cloning and sequence analysis. The open reading frame encodes a 441-amino acid polypeptide with a calculated molecular mass of 48,755 Da. Whole-mount in situ hybridization indicates that beta M mRNA is predominantly expressed in neuronal tissues. Transcription of beta M mRNA is evident from stage 13/14 of embryogenesis up to adulthood. Different expression patterns of splice variants were found in larvae and in adult fly heads. Amino acid identity between beta M and mammalian beta subunits is lower (66-68%) than within mammalian beta subunits (74-80%). Calculation of a phylogenetic tree indicates that beta M is an ancestral form of the four distinct beta subunit gene products identified in mammalian tissues so far. Despite these sequence differences, beta M is able to enhance endogenous calcium channel activity in Xenopus laevis oocytes as well as dihydropyridine binding to membranes from COS 7 cells transfected with rabbit heart alpha 1 cDNA in the same manner as was previously shown for mammalian beta subunits.
Grabner
M
M
Institut für Biochemische Pharmakologie, Universität Innsbruck, Austria.
Wang
Z
Z
Mitterdorfer
J
J
Rosenthal
F
F
Charnet
P
P
Savchenko
A
A
Hering
S
S
Ren
D
D
Hall
L M
LM
Glossmann
H
H
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D004095:Dihydropyridines / Q000494:pharmacology; D004175:Diptera / Q000235:genetics*; D004553:Electric Conductivity; D007814:Larva; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D015220:Calcium Channels; D017931:DNA Primers; D004095:Dihydropyridines; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C038806:1,4-dihydropyridine