text: Northern blot.
  A mouse embryonic tissue Northern blot filter (Seegene, Rockville, Maryland, United States) was hybridized with a Sox6 probe generated by RT-PCR (nucleotides 1353-1927) and labeled with [alpha-32P]dCTP, by random primer labeling (RediprimeII; Amersham Biosciences, Buckinghamshire, England, United Kingdom). The hybridization was performed in phosphate buffered 7% SDS hybridization solution. Blots were washed with 0.2x SSC, 1% SDS at 60 degreesC prior to exposure to X-ray film (Kodak, Rochester, New York, United States) at -80 degreesC for 6 d. 
  