Specific regulation of low-abundance transcript variants encoding human Acyl-CoA binding protein (ACBP) isoforms

Area of Science:

• Molecular Biology
• Genomics
• Biochemistry

Background:

• Eukaryotic transcriptome annotation is extensive, yet regulation of low-abundance transcripts remains poorly understood.
• Human acyl-CoA binding protein (ACBP) is a crucial housekeeping protein with diverse functions.
• Novel low-abundance transcript variants of ACBP were identified.

Purpose of the Study:

• To investigate the regulation of newly identified low-abundance ACBP transcript variants.
• To determine the tissue-specific distribution and responsiveness of these transcripts.
• To elucidate the regulatory mechanisms and biological implications of ACBP transcript variants.

Main Methods:

• Screening of human expressed sequence tags and ab initio gene prediction.
• RT-PCR, real-time RT-PCR, and rapid amplification of cDNA ends-PCR across five human tissues.
• Promoter analysis, subcellular localization studies in HepG2 cells.

Main Results:

• Identified authentic low-abundance ACBP transcripts generated via alternative promoters and exons.
• Demonstrated tissue-specific distribution and responsiveness to glucose and insulin.
• Revealed differential regulation by sterol regulatory element-binding protein-2, hepatocyte nuclear factor-4α, and nuclear factor κB (NF-κB).
• Showed distinct subcellular localization of ACBP isoforms.
• Established ACBP as an NF-κB target, linking fatty acid metabolism with inflammation.

Conclusions:

• Low-abundance transcripts are regulated similarly to high-abundance ones.
• ACBP transcript variant regulation involves key metabolic and inflammatory transcription factors.
• Findings link fatty acid metabolism to inflammation via ACBP regulation by NF-κB.