AtMYB44 suppresses transcription of the late embryogenesis abundant protein gene <i>AtLEA4-5</i>

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>AtLEA4-5 is a member of the group 4 late embryogenesis abundant (LEA) proteins, which are involved in the tolerance of water deficit in <I>Arabidopsis thaliana</I>. Chromatin immunoprecipitation assays revealed that the transcription factor AtMYB44 bound directly to the <I>AtLEA4-5</I> gene promoter region under normal conditions, but was eliminated in response to osmotic stress (mannitol treatment). A quantitative reverse transcription PCR assay revealed that transcription of the <I>AtLEA4-5</I> gene was induced in response to either salt (salinity) or mannitol (osmosis) treatment. The abiotic stress-induced increase in <I>AtLEA4-5</I> transcripts was reduced in <I>35S:AtMYB44</I> transgenic plants, indicating that the transcription factor AtMYB44 represses gene transcription. More RNA polymerase II stalled at the transcription start site (TSS) of the <I>AtLEA4-5</I> gene loci under osmotic stress, but the increment was reduced in the <I>35S:AtMYB44</I> plants. Histones are evicted from the promoter region under osmotic stress; however, histone eviction was hampered in the <I>35S:AtMYB44</I> plants. Under osmotic stress, the acetylated histones remaining at the TSS region was significantly lower in the <I>35S:AtMYB44</I> plants compared with wild-type plants. These results indicate that AtMYB44 suppresses polymerase-mediated transcription of the <I>AtLEA4-5</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AtMYB44 binds to the <I>AtLEA4-5</I> gene promoter region under normal conditions. </LI> <LI> Osmotic stress eliminates AtMYB44 from the <I>AtLEA4-5</I> gene promoter. </LI> <LI> AtMYB44 suppresses polymerase-mediated transcription of <I>AtLEA4-5.</I> </LI> <LI> AtMYB44 reduces nucleosome acetylation in the <I>AtLEA4-5</I> TSS proximal region. </LI> </UL> </P>