A team at the Salk Institute (Salk) has shown a genefamily that
regulates parts of thegenomethat are turned off in a tissue-specific manner.

The CLASSY gene family (/CLSY/1â??4) essentially controls where the genome
is marked by DNA methylation, the addition of methyl chemical groups to
the DNA acting like tags saying, "turn off." The research team found
that/CLSY/genes were expressed differently depending on plant tissue
type. Using Arabidopsis, the Salk team discovered that the CLASSY gene
family (/CLSY/ 1â??4) acts at different locations depending on the tissue,
revealing how diverse patterns of methylation are generated during plant
development. For example, all four/CLSY genes/were expressed in flower
buds, while/CLSY3/was strongly expressed in ovules and/CLSY1/was
expressed in leaf and rosette tissues.

The research team compared plants with mutant/CLSY/genes against
wild-type plants and found that depending on the tissue, different
combinations of/CLSY/family members, or even individual/CLSY/proteins,
controlled small RNA and DNA methylation patterns at thousands of sites
throughout the genome. The research results show the role of/CLSY/genes
in shaping the tissues' epigenetic landscape.

Plants rely on the CLASSY gene family to diversify their epigenomes -
Salk Institute for Biological Studies
[www.salk.edu]