Sox genes share a highly conserved DNA-binding motif, the HMG (high mobility 
group)-box domain, and have diverse roles in vertebrate embryonic development. A 
novel SRY-related cDNA (temporarily called Sox33) isolated from the Chinese 
alligator (Alligator sinensis) is 1,819 bp in length, with an open reading frame 
from 220 to 1113 bp, encoding a protein of 298 amino acids. Two putative 
polyadenylation signal sequences (AATAAA) are present upstream of the poly(A) 
tail in the 3' UTR (at 1255-1260 and 1774-1779). The putative protein contains 
an HMG-box domain most closely related to hSox12, mSox4, rtSox11, and mSox11 
homologs, indicating that alligator Sox33 belongs to group C in the Sox gene 
family. Alligator adult and developing tissues were tested for Sox33 mRNA by 
independent Northern blots using a 336-bp probe (at 907-1243) between the 
HMG-box and the poly(A) site I and a 277-bp probe (at 1477-1754) between the two 
polyadenylation sites. Two transcripts (1.3 kb and 1.8 kb) in developing brain 
and one (1.8 kb) in adult brain were identified by the 336-bp probe; only one 
transcript (1.8 kb) in developing and adult brains was detected by the 277-bp 
probe. The results suggest that alligator Sox33 may use a different 
polyadenylation mechanism in the developing brain and play a role in the 
development and maintenance of the nervous system.