CMT X: Human oligodendrocytes express Cx31.3: Function and interactions with Cx3

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Neurobiol Dis. 2008 Feb 15

Human oligodendrocytes express Cx31.3: Function and interactions with

Cx32 mutants.

Sargiannidou I, Ahn M, Enriquez AD, Peinado A, Reynolds R, Abrams C,

Scherer SS, Kleopa KA.

Clinical Neurosciences Section, Cyprus Institute of Neurology and

Genetics, Nicosia, Cyprus.

Murine oligodendrocytes express the gap junction (GJ) proteins

connexin32 (Cx32), Cx47, and Cx29. CNS phenotypes in patients with X-

linked Charcot-Marie-Tooth disease may be caused by dominant effects

of Cx32 mutations on other connexins. Here we examined the expression

of Cx31.3 (the human ortholog of murine Cx29) in human brain and its

relation to the other oligodendrocyte GJ proteins Cx32 and Cx47.

Furthermore, we investigated in vitro whether Cx32 mutants with CNS

manifestations affect the expression and function of Cx31.3. Cx31.3

was localized mostly in the gray matter along small myelinated fibers

similar to Cx29 in rodent brain and was co-expressed with Cx32 in a

subset of human oligodendrocytes. In HeLa cells Cx31.3 was localized

at the cell membrane and appeared to form hemichannels but no GJs.

Cx32 mutants with CNS manifestations were retained intracellularly,

but did not alter the cellular localization or function of co-

expressed Cx31.3. Thus, Cx31.3 shares many characteristics with its

ortholog Cx29. Cx32 mutants with CNS phenotypes do not affect the

trafficking or function of Cx31.3, and may have other toxic effects

in oligodendrocytes.