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DIURNAL CELL DIVISION REGULATED BY GATING THE G 1 /S TRANSITION IN ENTEROMORPHA COMPRESSA (CHLOROPHYTA) 1
Author(s) -
Kuwano Kazuyoshi,
Sakurai Ryousuke,
Motozu Yoshitaka,
Kitade Yukihiro,
Saga Naotsune
Publication year - 2008
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2008.00477.x
Subject(s) - biology , photoperiodism , darkness , cell division , chlorophyta , gating , circadian rhythm , botany , thallus , cell cycle , circadian clock , microbiology and biotechnology , biophysics , cell , algae , biochemistry , neuroscience
The cell‐cycle progression of Enteromorpha compressa (L.) Nees (= Ulva compressa L.) was diurnally regulated by gating the G 1 /S transition. When the gate was open, the cells were able to divide if they had attained a sufficient size. However, the cells were not able to divide while the gate was closed, even if the cells had attained sufficient size. The diurnal rhythm of cell division immediately disappeared when the thalli were transferred to continuous light or darkness. When the thalli were transferred to a shifted photoperiod, the rhythm of cell division immediately and accurately synchronized with the shifted photoperiod. These data support a gating‐system model regulated by light:dark (L:D) cycles rather than an endogenous circadian clock. A dark phase of 6 h or longer was essential for gate closing, and a light phase of 14 h was required to renew cell division after a dark phase of >6 h.