Calmodulin-binding proteins are developmentally regulated in gametes and embryos of fucoid algae.
Calcium-binding proteins and calmodulin-binding proteins were identified in gametes and zygotes of the marine brown algae Fucus vesiculosus, Fucus distichus, and Pelvetia fastigiata using gel (SDS-PAGE) overlay techniques. A calcium current appears to be important during cell polarization in fucoid zygotes (K.R. Robinson and L.F. Jaffe, 1975, Science 187, 70-72; K.R. Robinson and R. Cone, 1980, Science 207, 77-78), but there are no biochemical data on calcium-binding proteins in these algae. By using a sensitive 45Ca2+ overlay method designed to detect high-affinity calcium-binding proteins, at least 9-11 polypeptides were detected in extracts of fucoid gametes and zygotes. All samples had calcium-binding proteins with apparent molecular weights of about 17 and 30 kDa. A 17-kDa calcium-binding protein was purified by calcium-dependent hydrophobic chromatography and was identified as calmodulin by immunological and enzyme activator criteria. A 125I-calmodulin overlay assay was used to identify potential targets of calmodulin action. Sperm contained one major calmodulin-binding protein of about 45 kDa. Eggs lacked major calmodulin-binding activity. A 72-kDa calmodulin-binding protein was prominent in zygotes from 1-65 hr postfertilization. Both calmodulin-binding proteins showed calcium-dependent binding activity. Overall, the data suggest that the appearance and distribution of certain calcium-binding and calmodulin-binding proteins are under developmental regulation, and may reflect the different roles of calcium during fertilization and early embryogenesis.
Brawley
S H
SH
Department of Biology, Vanderbilt University, Nashville, Tennessee 37235.
Roberts
D M
DM
D001345:Autoradiography; D002132:Calcium Radioisotopes; D002135:Calcium-Binding Proteins / Q000032:analysis; D002147:Calmodulin / Q000032:analysis; D002148:Calmodulin-Binding Proteins / Q000032:analysis*; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D056890:Eukaryota / Q000254:growth & development*; D015151:Immunoblotting; D008297:Male; D008970:Molecular Weight; D010063:Ovum / Q000032:analysis; D000459:Phaeophyceae / Q000032:analysis / Q000254:growth & development*; D013094:Spermatozoa / Q000032:analysis; D015053:Zygote / Q000032:analysis
D002132:Calcium Radioisotopes; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins