122,064 Kb, 12 exons. Exon 1, containing the initiation ATG, is the largest (454 bp) and exon 7 the smallest (59 bp). Exon 12 includes the termination TAA codon. Introns 1 and 9 are the largest (73132 bp) and smallest (281 bp), respectively.

The strongest expression was seen in placenta, lung, spleen and intestine, and the weakest in heart, brain, skeletal muscle, thymus, colon and leukocytes. In fetal tissues, the weakest expression was detected in brain and heart. A splice variant, lacking exon 2, was found in placenta, spleen and fetal liver

519 amino acids, 57 kDa. The amino acid sequence spanning residues 291-356 of the predicted human CREB3L2 protein contains a consensus B-ZIP domain highly similar to that in the CREB3L1, CREB3L3, CREB3L4, CREB3 and Drosophila Bbf-2 transcription factors with 80, 60, 59, 56 and 71% identity, respectively. It also contains the amino acid sequence RRKKKEY which is exactly conserved among CREB, CREM, ATF1, ATF6 and CREBL1. The leucine zipper motif of CREB3L2 is similar to that in CREB3L3 and CREB3L4 (pattern L-X6-C-X6-L-X6-L-X6-L-X6-L). It contains six repeats and consists of five leucines and one cysteine at the second heptad position (amino acid 328) of the leucine zipper. Downstream of the B-ZIP domain, CREB3L2 also contains a hydrophobic region, which was predicted to be an a-helical transmembrane domain (position 376-397; GTCLMVVVLCFAVAFGSFFQGY) by the prediction program PSORT II. This structural feature is also seen in the other members of the family, i.e. CREB3L1, CREB3L3, CREB3 and CREB3L4.

B-ZIP transcription factor

CREB3L2 is a member of the old astrocyte specifically induced substance (OASIS) DNA binding and basic leucine zipper dimerization (B-ZIP) family of transcription factors, together with CREB3L1 (also known as OASIS), CREB3L3, CREB3 and CREB3L4.