Molecular analysis of the human cytoglobin mRNA isoforms

Area of Science:

• Molecular Biology
• Genomics
• Cancer Research

Background:

• Vertebrate cytoglobin (Cygb) is a ubiquitous globin with proposed roles in nitric oxide metabolism, RONS scavenging, and cancer. Alternative splicing is a known mechanism for expanding gene function.
• The functional diversity of Cygb may be influenced by alternative mRNA splicing, but this has not been extensively studied.

Purpose of the Study:

• To investigate the existence and potential functional diversity of alternative mRNA isoforms of the human CYGB gene.
• To characterize the expression patterns of CYGB isoforms, particularly in the context of hepatoblastoma.

Main Methods:

• Mining of cDNA data and molecular analysis to identify human CYGB mRNA isoforms.
• RNA-sequencing (RNA-seq) analysis of public datasets from various human tissues and cells.
• Comparative transcriptomics and flow cytometry using gene-edited CYGB knockout (CYGB-/-) HepG2 cells.

Main Results:

• Five alternative mRNA isoforms (V-1 to V-5) for the human CYGB gene were identified.
• The canonical CYGB V-1 isoform is the primary transcript in most tissues, while V-3 is predominant in hepatoblastoma cell lines and liver tissues.
• CYGB V-3 is transcribed from an alternative promoter and encodes a potentially N-terminally truncated protein. No knockout phenotype was observed in CYGB-/- cells, and the function of V-3 remains unclear.

Conclusions:

• The human CYGB gene exhibits greater transcriptional complexity than previously recognized, expressing alternative mRNA isoforms.
• The specific biological functions of the identified alternative CYGB transcripts, including the predominant V-3 isoform in liver cancer, require further experimental investigation.