Differential
gene expression in maize mediator of paramutation1 mutants
Heather
Whittington
Marquette
University
Milwaukee,
WI
Mentor:
Dr. Jane E. Dorweiler
Remodeling
the structure of chromatin is a crucial method of epigenetic gene regulation.
By altering how loose or tightly the chromatin is packaged, the cell can
control which genes are expressed as a result of their accessibility to
transcription machinery. In maize, an important player in this mechanism
may be the gene mediator of paramutation (mop1), but the exact identity
and function of this gene is unknown. Due to the varied abnormal phenotypes
displayed by plants with a recessive mutation in the gene, it has been
postulated that mop1 encodes a protein involved in repressive chromatin
remodeling and/or assembly.
One
of the atypical phenotypes seen in homozygous mop1-1 mutants is a five
to seven day delay in flowering. Knowledge of why this delay occurs may
reveal the function of the MOP1 protein and may also illuminate mechanisms
of chromatin remodeling. Since MOP1 is thought to play role in the remodeling
of chromatin, it is probable that altered expression of one or several
genes that control flowering causes the abnormal flowering phenotype. Unfortunately,
flowering in maize has not been well studied, and only a few genes have
been identified that control the change from the vegetative phase to the
reproductive phase. Thus, maize genes that are homologous to Arabidopsis
flowering time genes were identified, and their expression will be assayed.
In
order to compare gene expression, RNA was extracted from the tassels of
homozygous mop1-1 mutants, plants heterozygous for the mutation, and wild
type plants. Reverse transcription polymerase chain reaction (RT-PCR) was
then used to assay the expression of one of the identified maize homologs.
Once RT-PCR data is obtained and confirmed through gel electrophoresis,
the expression of this gene in the various mop1 genotypes can then be compared
through quantification of the intensities of the bands created by the PCR
products. |
