Establishment of a highly sensitive and specific exon-trapping system

Area of Science:

• Genomics
• Molecular Biology
• Cancer Genetics

Background:

• Identifying functional exons within large genomic regions is challenging.
• Human chromosome 11q13 is implicated in various cancers due to observed DNA amplification.
• Efficient methods are needed to screen for novel genes in cancer-associated genomic loci.

Purpose of the Study:

• To establish a highly sensitive and specific exon-trapping system (SETS) for rapid exon isolation.
• To apply SETS to screen large genomic DNA fragments from human chromosome 11q13.
• To identify potential cancer-related genes within the screened region.

Main Methods:

• Developed a novel exon-trapping vector (pMHC2).
• Cloned partially digested genomic DNA fragments into the vector.
• Transfected constructs into COS-7 cells for in vivo splicing.
• Harvested and amplified mature mRNA using reverse transcription-PCR (RT-PCR).
• Identified putative exons by PCR product size and subsequent cloning.

Main Results:

• The exon-trapping system (SETS) efficiently isolates exons from DNA fragments >300 kilobase pairs.
• Successfully screened 300-kilobase-pair segments from human chromosome 11q13.
• Identified exon 2 of the HST1 gene and other transcribed sequences.

Conclusions:

• SETS provides a rapid and direct method for cloning exons from large genomic DNA.
• The identified sequences from chromosome 11q13 may contribute to understanding cancer development.
• This system facilitates the discovery of novel genes in complex genomic regions.