Functional Analysis of Sheep POU2F3 Isoforms.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• POU domain class 2 transcription factor 3 (POU2F3) is crucial for keratinocyte function.
• Four sheep POU2F3 transcript variants (POU2F3-1 to -4) were previously identified, encoding three protein isoforms (POU2F3-1 to -3).
• Functional distinctions among these POU2F3 isoforms were previously unknown.

Purpose of the Study:

• To investigate the tissue expression patterns of sheep POU2F3 transcript variants.
• To elucidate the functional differences in cell proliferation among the three POU2F3 protein isoforms.
• To assess the impact of POU2F3 isoforms on the promoter activity of keratin 14 (KRT14) and matrix metalloproteinase 19 (MMP19) genes.

Main Methods:

• Quantitative RT-PCR was employed to analyze POU2F3 transcript expression across various adult sheep tissues.
• Cell proliferation assays were conducted using sheep fetal fibroblasts and HaCaT cells to evaluate the effects of POU2F3 isoform overexpression.
• Dual luciferase reporter assays were performed to measure the influence of POU2F3 isoforms on KRT14 and MMP19 promoter activities.

Main Results:

• POU2F3 transcripts were ubiquitously expressed in all tested adult sheep tissues, with POU2F3-1 showing higher expression in skin.
• Overexpression of any POU2F3 isoform significantly inhibited sheep fetal fibroblast and HaCaT cell proliferation.
• POU2F3-3 exhibited a less pronounced inhibitory effect on cell proliferation and gene promoter activities compared to POU2F3-1 and POU2F3-2.

Conclusions:

• The three sheep POU2F3 isoforms demonstrate conserved roles in regulating cell proliferation and gene expression.
• Functional differences exist among POU2F3 isoforms, with POU2F3-3 having a comparatively weaker inhibitory impact.
• These findings contribute to understanding the nuanced functions of POU2F3 isoforms in sheep biology.