Array analysis of gene expression in connexin-43 null astrocytes.

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Connexin-43 (Cx43) is the primary gap junction protein in the brain, predominantly found between astrocytes.
• While astrocyte morphology is similar in Cx43-null (KO) and wild-type (WT) mice, KO astrocytes show a reduced growth rate in culture.

Purpose of the Study:

• To investigate the impact of Cx43 deletion on gene expression in astrocytes.
• To identify genes, including cell cycle proteins, affected by the absence of Cx43.

Main Methods:

• Utilized DNA arrays to compare gene expression patterns in cultured astrocytes from sibling Cx43-null and WT mice.
• RNA samples were cohybridized with a reference pool on gene arrays containing 8,975 mouse DNA sequences.
• Statistical analysis incorporated normal variability to compare expression levels between WT and KO samples.

Main Results:

• Significant changes in gene expression were observed in Cx43-null astrocytes: 4.1% of spots showed decreased hybridization and 9.4% showed increased hybridization (P < 0.05).
• These differentially expressed genes encode 252 known proteins, including transcription factors, channels, transporters, growth/death signals, enzymes, and cell adhesion molecules.
• Many identified proteins were not previously linked to gap junctions.

Conclusions:

• Cx43 deletion has a substantial impact on astrocyte gene expression, affecting a wide range of cellular processes.
• Gap junction protein expression influences numerous cellular functions beyond intercellular communication.
• These findings suggest a broader regulatory role for Cx43 in astrocyte biology.