OCT-6 (SCIP TST-1) IS EXPRESSED IN SCHWANN-CELL PRECURSORS, EMBRYONICSCHWANN-CELLS, AND POSTNATAL MYELINATING SCHWANN-CELLS - COMPARISON WITH OCT-1, KROX-20, AND PAX-3/

The POU domain transcription factor Oct-6 (SCIP/ Tst-1) is likely to c ontrol important stages of Schwann sell development, including the ini tiation of myelination around hh-th, Mere, we use immunocytochemical a nd reverse transcriptase-polymerase chain reaction techniques to exami ne Oct-6 earlier in nerve development, to test the Idea that Oct-6 has an additional role in Schwann cell precursors or early embryonic Schw ann cells, a possibility raised by previous studies on transgenic mice , Consistent with this, we bind law but unambiguous levels of Oct-6 mR NA and protein in Schwann cell precursors of mouse and rat (nerves fro m 12- and 14-day-old embryos, respectively), with expression levels gr adually increasing during early Schwann cell development and towards b irth. Unexpectedly, Oct-6 immunoreactivity is clearly present in nucle i of most myelinating cells at least as late as postnatal day 12, Furt hermore, many nonmyelinating Schwann cells express Oct-6 inn adult lif e. A comparison of Oct-6 mRNA with other Schwann cell transcription fa ctors-namely, Oct-1, Krox-20, and Pax-3-reveals that each factor exhib its strong developmental regulation and a unique expression pattern in embryonic nerves, Therefore, they are likely to play distinct regulat ory roles in early development of the Schwann cell lineage. (C) 1996 W iley-Liss, Inc.