TABLE 3.
Total cellular and mitochondrial abundance of 15 tRNA isoacceptors of T. brucei
| tRNA (anticodon) | No. of molecules per cell | No. of molecules per mitochondrion (% of total) |
|---|---|---|
| Asn (GUU) | 13,500 | 370 (2.7) |
| Asp (GUC) | 40,600 | 2,430 (6.0) |
| Cys (GCA) | 36,800 | 1,770 (4.8) |
| Gln (UUG) | 61,500 | 1,210 (2.0) |
| Glu (CUC) | 52,300 | 1,420 (2.7) |
| Ile (UAU) | 47,000 | 3,520 (7.5) |
| Leu (AAG) | 130,000 | 3,580 (2.8) |
| Leu (CAA) | 220,100 | 7,700 (3.5) |
| Leu (CAG) | 121,300 | 1,210 (1.0) |
| Leu (UAG) | 60,700 | 1,820 (3.0) |
| Lys (CUU, UUU) | 113,700 | 4,090 (3.6) |
| Met-i (CAU) | 1,900 | 4 (0.2) |
| Met-e (CAU) | 15,600 | 880 (5.6) |
| Phe (GAA) | 36,400 | 1,350 (3.7) |
| Tyr (GUA) | 6,100 | 410 (6.8) |
| Met-i | ND | ND (0.3)a |
| Met-e | ND | ND (5.0)a |
| Leu (CAA) | ND | ND (3.2)a |
| 0-Leu∗ (CAA)b | 3,600 | 100 (2.9)a |
| 10-Leu∗ (CAA)b | 15,200 | 460 (3.0)a |
| 59-Leu∗ (CAA)b | 39,900 | 1,160 (2.9)a |
| 216-Leu∗ (CAA)b | 49,200 | 1,480 (3.0)a |
a
Mitochondria were isolated by digitonin extraction (see Materials and Methods).
b
Tagged tRNALeu(CAA) expressed in transgenic T. brucei (see Fig. 6). The abundance of the tRNA isoacceptor was determined by quantitative Northern analysis using the corresponding in vitro-transcribed tRNAs as marker. Unless otherwise indicated, mitochondria were isolated by the hypotonic procedure outlined in Materials and Methods.