A presumptive developmental role for a sea urchin cyclin B splice variant.
We show that a splice variant-derived cyclin B is produced in sea urchin oocytes and embryos. This splice variant protein lacks highly conserved sequences in the COOH terminus of the protein. It is found strikingly abundant in growing oocytes and cells committed to differentiation during embryogenesis. Cyclin B splice variant (CBsv) protein associates weakly in the cell with Xenopus cdc2 and with budding yeast CDC28p. In contrast to classical cyclin B, CBsv very poorly complements a triple CLN deletion in budding yeast, and its microinjection prevents an initial step in MPF activation, leading to an important delay in oocyte meiosis reinitiation. CBsv microinjection in fertilized eggs induces cell cycle delay and abnormal development. We assume that CBsv is produced in growing oocytes to keep them in prophase, and during embryogenesis to slow down cell cycle in cells that will be committed to differentiation.
Lozano
J C
JC
Centre National de la Recherche Scientifique, URA 2156, Laboratoire Arago, BP 44, F 66651 Banyuls sur mer Cedex France.
Schatt
P
P
Marquès
F
F
Peaucellier
G
G
Fort
P
P
Féral
J P
JP
Genevière
A M
AM
Picard
A
A
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D003001:Cloning, Molecular; D019926:Cyclin B / Q000235:genetics* / Q000502:physiology*; D016200:Maturation-Promoting Factor / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology; D012333:RNA, Messenger / Q000737:chemistry; D012617:Sea Urchins / Q000196:embryology*; D016415:Sequence Alignment
D019926:Cyclin B; D012333:RNA, Messenger; D016203:CDC2 Protein Kinase; D016200:Maturation-Promoting Factor