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Published on: January 24, 2025
Enhanced Expression of FRA16B using AT-Rich DNA Binding Chemicals in a Woman with Secondary Amenorrhoea
Gunasekaran Bhavani1, S Sivaprakash2, Chandra R Samuel3
1Ph.D. Research Scholar, Department of of Genetics, Dr. ALM Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, Tamil Nadu, India.
Abstract:
Fragile sites represent regions of chromatin that fail to compact during mitosis. Based on the prevalence and pattern of inheritance they are classified as rare fragile sites or common fragile sites. Rare fragile sites either occur spontaneously or can be induced by certain AT-specific binding chemicals namely distamycin, Hoechst 33258, Berenil and others. The most common of all rare autosomal fragile sites is fra(16)(q22) with a heterozygote frequency of ~5%. FRA16B results from an expansion of a 33 bp AT-rich Minisatellite repeat. These rare forms are usually heritable and segregate in a Mendelian fashion. The proband who was referred for secondary amenorrhoea, revealed 46,XX,fra(16)(q22.1)pat karyotype. Her father and younger sibling were also found to be carriers. This study aimed to delineate the genotypic and phenotypic features exhibited by these carriers and to evaluate FRA16B expression using AT-specific binding chemicals. The additives employed were Berenil, BrdU and Hoechst 33258. Berenil at a concentration of 150 µg/ml showed the highest expression of FRA16B. Although the recent breakthrough in molecular characterization of fragile sites plays a critical role in comprehending their association with various diseases, the physiological link between them and amenorrhoea is not clearly understood.
Insights
Fragile site FRA16B, linked to secondary amenorrhea, is a heritable genetic condition. This study investigated its expression and carrier features, finding Berenil effectively induced FRA16B. Further research is needed to understand the amenorrhea connection.
Area of Science:
- Genetics
- Molecular Biology
- Human Physiology
Background:
- Fragile sites are chromatin regions that resist compaction during mitosis, classified as rare or common based on inheritance patterns.
- Rare fragile sites, like FRA16B, are often heritable and linked to specific genetic mutations, such as expanded AT-rich minisatellite repeats.
Observation:
- A patient with secondary amenorrhea presented with a 46,XX,fra(16)(q22.1)pat karyotype, with affected father and sibling.
- FRA16B expression was evaluated using AT-specific chemicals, with Berenil at 150 µg/ml demonstrating the highest induction.
Findings:
- The study delineated genotypic and phenotypic features of FRA16B carriers.
- Berenil proved effective in inducing FRA16B expression, highlighting its utility in studying fragile site characteristics.
Implications:
- Understanding FRA16B's molecular basis and expression is crucial for comprehending its role in genetic disorders.
- Further investigation is required to elucidate the physiological link between FRA16B and secondary amenorrhea, despite advances in fragile site characterization.
