Mechanisms of transcriptional activation of the Col6a1 gene during Schwann cell differentiation

A transgenic mouse line expressing the lacZ reporter under the control of a regulatory region of the col6a1 gene has been used to investigate differentiation of Schwann cells. The data suggest that: (1) activation of col6a1 gene transcription in the peripheral nervous system is part of the differentiation program of Schwann cells from neural crest cells stimulated by neuregulins; (2) once the Schwann cell precursors have acquired the competence of transcribing the col6a1 gene, transcriptional regulation becomes independent from neuregulins and is modulated by different mechanisms, including cell cycle; (3) activation of transgene expression after birth in sciatic nerves corresponds to the time of withdrawal of immature Schwann cells from the cell cycle and the beginning of their differentiation into myelinating Schwann cells.