Table 2.
Summary of genes that exhibit alternative first exons
| Category and gene | No. of alternative first exons | Protein isoforms |
|---|---|---|
| Globins | ||
| None | NA | NA |
| Heme biosynthetic enzymes | ||
| ALAS2 | 2 | No |
| HMBS | 2 | Yes |
| UROS | 2 | No |
| Transcription factors | ||
| GATA-1* | 2 | No |
| GATA-2 | 2 | No |
| MAFG | 2 | No |
| NFE2L1 | 2 | Yes |
| NFE2L2 | 2 | Yes |
| NFE2 | 2 | No |
| Cytoskeletal proteins | ||
| ADD1 | 2 | No |
| ADD2 | 2 | No |
| ADD3 | 2 | No |
| ANK1* | 3 | Yes |
| EPB41* | 3 | Yes |
| EPB49 | 4 | No |
| TPM1 | 2 | Yes |
| Plasma membrane proteins | ||
| ACHE* | 4 | Yes |
| AE1* | 2 | Yes |
| CD47 | 2 | Yes |
| CD147 | 2 | Yes |
| CD151 | 2 | No |
| FUT3 | 2 | Yes |
| GYPE | 2 | Yes |
| SLC14A1 | 3 | Yes |
| HK1 | 3 | Yes |
| NT5C3 | 2 | No |
| Glycolytic enzymes etc | ||
| A4GALT | 2 | Yes |
| ABO | 2 | Yes |
| ALDOA | 3 | Yes |
| B3GALT3 | 2 | Yes |
| G6PD | 2 | Yes |
| GCNT2 | 3 | Yes |
| GSR | 2 | Yes |
| GSS | 2 | No |
| PFKM | 2 | Yes |
| PKLR | 2 | Yes |
A considerable number of the 103 genes we analyzed in this study display 5′ end complexity. In all, we found 36 genes that show alternative first exons (35%), and they are listed here by functional category. Information about the number of alternative exons, as well as whether these exons lead to the synthesis of protein isoforms with different N-termini, is also provided.
NA indicates not applicable.