Résumé
Methylation of cytosine in the 5 position of the pyrimidine ring
is a major modification of the DNA in most organisms. In eukaryotes,
the distribution and number of 5-methylcytosines (5mC) along the
DNA is heritable but can also change with the developmental state
of the cell and as a response to modifications of the environment.
While DNA methylation probably has a number of functions, scientific
interest has recently focused on the gene silencing effect methylation
can have in eukaryotic cells. In particular, the discovery of changes
in the methylation level during cancer development has increased
the interest in this field. In the past, a vast amount of data has
been generated with different levels of resolution ranging from
5mC content of total DNA to the methylation status of single nucleotides.
We present here a database for DNA methylation data that attempts
to unify these results in a common resource. The database is accessible
via WWW (http://www.methdb.de).
It stores information about the origin of the investigated sample and
the experimental procedure, and contains the DNA methylation data.
Query masks allow for searching for 5mC content, species, tissue,
gene, sex, phenotype, sequence ID and DNA type. The output lists
all available information including the relative gene expression
level. DNA methylation patterns and methylation profiles are shown
both as a graphical representation and as G/A/T/C/5mC-sequences
or tables with sequence positions and methylation levels, respectively.