THE PLANT CELL, Vol 7, Issue 12 1989-2000, Copyright © 1995 by American Society of Plant Biologists
Tissue-Specific Accumulation of MURB, a Protein Encoded by MuDR, the Autonomous Regulator of the Mutator Transposable Element Family
M. J. Donlin, D. Lisch and M. Freeling
Department of Plant Biology, University of California-Berkeley, Berkeley, California 94720
The Mutator (Mu) system of transposable elements is highly mutagenic and
can maintain high levels of activity through multiple generations due to
frequent transpositions of both its autonomous and nonautonomous
components. This family also shows pronounced developmental regulation.
Most notable is the very low frequency of germinal reversions, despite the
high levels of somatic transpositions and excisions, and the high frequency
of germinally transmitted duplication events. Here, we report the
production of antibodies raised against MURB, one of two proteins encoded
by MuDR, the autonomous regulator of the Mu family. Immunolocalizations
performed using anti-MURB antibodies reveal that this protein is present in
specific tissues during male inflorescence development. Throughout much of
development, MURB is detected at the highest levels in cell lineages that
may find themselves in the germ line, but no MURB is detected in microspore
mother cells. These cells are the direct precursors to pollen. Based on
these observations as well as previous data, we discuss the relationship
between the expression of MURB and developmental regulation of Mu activity.
