Author

Maria Kontos

Document Type

Honors Capstone Project

Date of Submission

Spring 5-1-2013

Capstone Advisor

Dr. Eleanor Maine

Honors Reader

Dr. John Belote

Capstone Major

Biology

Capstone College

Arts and Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biology

Abstract

Chromatin is the combination of DNA and the proteins binding to DNA in the cell nucleus. The primary proteins associated with chromatin are histones, which compact the DNA. The DNA strand wraps around the histone octamer core complex forming a structure called the nucleosome. Posttranslational modifications of histones alter chromatin structure. Generally speaking, acetylated histones are associated with active gene expression whereas deacetylated histones are associated with repressed gene expression. Histone deacetylases, which function as a multi protein complex, remove acetyl groups resulting in altered DNA-histone binding affinities. One major histone deacetylase (HDAC) complex is the SIN-3 HDAC complex. SIN-3 acts as a “scaffold,” and is specifically thought to interact with certain DNA binding proteins and histone deacetylases to assemble this HDAC complex.

In C. elegans, when germ cells enter meiotic prophase I, the chromosomes coil becoming shorter and thicker, and homologous chromosomes pair and synapse. A chromosome that fails to pair with a partner and synapse (for example, the male X chromosome) accumulates a high level of a specific histone modification, histone H3 lysine 9 dimethylation (H3K9me2). This modification is associated with facultative heterochromatin assembly, which may result in transcriptional silencing. It was observed that loss of sin-3 function disrupts the H3K9me2 accumulation on unpaired X chromosomes in C. elegans hermaphrodites. Continuing the studies of a former student, Guang Yu Lee, a genetic approach has been taken to investigate which components of the SIN-3 complex contribute to the accumulation of H3K9me2 on nonsynapsed meiotic chromosomes.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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Biology Commons

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