Figure 2
Known isoforms of CPEB3 proteins. Gray boxes represented possible functional motifs. Dash-lined boxed represented deletions. For simplicity, the names of the motifs were only labeled in isoform 1. Poly-Q (poly-glutamine) and SA (poly serine-alanine) were two unique motifs of CPEB3 that were absent in the other three CPEBs. In the current study, each of the seven isoforms was named corresponding to the same numbered cDNA transcripts depicted in figure 1. Protein isoform 1 was the longest (716 aa) and may be derived from cDNA transcripts 1a-1d. One possible polymorphorism was located at the 372th amino acid of CPEB3 isoform 1: it was an N (asparagine) in [UniProtKB/Swiss-Prot: Q7TN99-Q7TN101] and [GenBank: AAQ20843] but a P (proline) in [GenBank: NP_938042, BAE27791, BAC41458]. Although the sequence of [GenBank: BAC41458] was reported as 722 aa, we presume it was 716 aa, since the first 6 amino acids QQAAQT preceding the 7th amino acid M (methionine) was likely to be falsely generated by the prediction software. Isoform 7 was derived from computational translation based on the novel transcript 7 identified in the current study. The upstream sequence of this isoform was yet to be determined; but the in-frame translation of the identified sequence would result in truncated RRM1 ending with four unique amino acids (LNWQ) and removal of RRM2. 197P represented the 197th serine, a phosphorylation site [31]. The positions of the gray-box and dash-lined-box motifs were indicated at the top and the bottom, respectively. The lengths, molecular sizes and accession numbers were indicated to the right.