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Evidence for introduction of a variable G1 phase at the midblastula transition during early development in axolotl
Author(s) -
Lefresne Jacques,
Andéol Yannick,
Signoret Jacques
Publication year - 1998
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.1998.t01-3-00004.x
Subject(s) - axolotl , cell cycle , dna replication , transition (genetics) , zygote , human fertilization , biology , dna synthesis , microbiology and biotechnology , chemistry , genetics , dna , cell , embryogenesis , embryo , regeneration (biology) , gene
After fertilization in axolotl, the synchronous cell cleavages are triphasic (S, G2 and M phases). Midblastula transition (MBT) begins at the ninth cleavage and is the consequence of lengthening of cell cycles. By spectro‐fluorometry and incorporation of 3 H thymidine into the nuclear DNA followed by autoradiography on individual cells, the time at which a G1 phase appears during early development was investigated. The present results show that the G1 phase was introduced for the first time at MBT and its duration was variable from one blastomere to another. This variability could account for lengthening of cell cycles and be required for zygotic transcriptions necessary for DNA replication. From this point of view, axolotl represents an interesting alternative amphibian model to identify regulators involved in the G1–S transition at MBT during early development.