Flowering Locus C (FLC) is a gene that is responsible for...

Flowering Locus C (FLC) is a gene that is responsible for flowering in certain plants. FLC is expressed in new seedlings, which prevents flowering. Upon exposure to cold temperatures, FLC expression decreases and the plant flowers. FLC is regulated through epigenetic modifications. What type of epigenetic modifications are present in new seedlings and after cold exposure? a. In new seedlings, histone acetylations are present; upon cold exposure, methylation occurs. b. In new seedlings, histone deacetylations are present; upon cold exposure, methylation occurs. c. In new seedlings, histone methylations are present; upon cold exposure, acetylation occurs. d. In new seedlings, histone methylations are present; upon cold exposure, deacetylation occurs

Flowering Locus C (FLC) is a gene that is responsible for flowering in certain plants. FLC is expressed in new seedlings, which prevents flowering. Upon exposure to cold temperatures, FLC expression decreases and the plant flowers. FLC is regulated through epigenetic modifications. What type of epigenetic modifications are present in new seedlings and after cold exposure?
a. In new seedlings, histone acetylations are present; upon cold exposure, methylation occurs.
b. In new seedlings, histone deacetylations are present; upon cold exposure, methylation occurs.
c. In new seedlings, histone methylations are present; upon cold exposure, acetylation occurs.
d. In new seedlings, histone methylations are present; upon cold exposure, deacetylation occurs

Key Concepts

Epigenetic Modifications

These are heritable changes in gene expression that occur without altering the underlying DNA sequence. They include a variety of chemical changes to DNA and its associated histone proteins, which can activate or silence gene expression and are crucial for regulating developmental processes, stress responses, and environmental adaptations.

Histone Methylation

This is a type of epigenetic modification involving the addition of methyl groups to histone proteins, particularly on specific lysine or arginine residues. Histone methylation can lead to either activation or repression of gene expression depending on the context and specific residue modified. In regulatory scenarios, it often establishes a repressive chromatin state that prevents transcription.

Histone Acetylation and Deacetylation

Histone acetylation involves the addition of acetyl groups to the lysine residues of histone tails, which typically results in a more relaxed chromatin structure and an increase in gene expression. In contrast, histone deacetylation removes these acetyl groups, leading to a tighter chromatin conformation that is generally associated with gene repression. These modifications enable dynamic regulation of gene expression in response to internal and external signals.

Vernalization

Vernalization is a process in plants where prolonged exposure to cold temperatures leads to epigenetic changes that alter the expression of genes controlling flowering. This mechanism ensures that flowering occurs at a favorable time of year by repressing or activating key regulatory genes through modifications such as changes in histone methylation or acetylation patterns.

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