|
Summary of Research Projects (Supports in 2003
Fiscal Year)
| Subjects |
Studies on the Histone Modification during Early Embryogenesis |
| Representative researcher |
Nagahama Institute of Bio-Science and Technology
Susumu IKEGAMI |
| Joint researcher |
Nagahama Institute of Bio-Science and Technology
Shinji OHTA |
| A histone heterodimer designated
embryonic histone d( H2B-H4 ), which contains an ε-(γ-glutamyl
)lysine cross-link between the 9th glutamine residue of histone
H2B
and the 5th lysine residue of histone H4 is formed during
starfish (Asterina pectinifera) embryogenesis. Immunoblot
analysis of nuclear preparations using a monoclonal antibody
against embryonic histone d(H2B-H4) as a probe showed that
embryonic histone d(H2B-H4) begins to appear in the midblastula
stage when the rate of cell proliferation decreases, and
its amount gradually increases up to the mid-gastrula stage.
The activity of nuclear transglutaminase begins to be expressed
at the midblastula stage and increases thereafter, which
parallels the increase in histone embryonic d(H2B-H4). The
sequence of the transglutaminase has been determined and
contains nuclear localization signals which are not found
in amino acid sequences of the other known trnaslutaminases.
The methyl ester of altacenoic acid, an anti-transglutaminase
substance from the bacterium Eupenicillium alutaceum inhibited
not only the enzymatic activity of nuclear transglutaminase
but also progression of embryonic development to arrest at
the early gastrula stage. These results implicate that the
transglutaminase present specifically in the nucleus catalyzes
histone dimerization which is essential for progression of
starfish embryonic development. |
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