Table I. Group I: novel C/D box snoRNAs guiding a rRNA methylation; group II: novel C/D box snoRNAs guiding a snRNA methylation; and group III: novel C/D box snoRNAs with unidentified targets.
| ERNS | Copies | cDNA | RNA | Homology | Modification | Antisense element | Location/comments | Accession No. |
|---|---|---|---|---|---|---|---|---|
| Group I | ||||||||
| MBI-43 | 4 | 221 | 240 | human | Um3787 in 28S | 13 nt (5′) | very long C/D box snoRNA; intron of sortin nexin 5 gene | AF357317 |
| MBII-55 | 4 | 59 | 65 | human | Um1288 in 18S | 12 nt (5′) | AF357318 | |
| MBII-82 | 2 | 64 | 72 | – | Gm3913 in 28S | 13 nt (5′) | AF357319 | |
| MBII-95 | 1 | 63 | 75 | human EST | Gm509 in 18S | 13 nt (3′) | AF357320 | |
| MBII-99 | 4 | 66 | 95/75 | human | Gm3868 in 28S | 13 nt (5′) | functional homologue of yeast snR190 | AF357321 |
| MBII-108 | 1 | 56 | – | human | Gm683 in 18S | 12 nt (3′) | AF357322 | |
| MBII-135 | 1 | 57 | 72 | rat, bovine | Um627 in 18S | 14 nt (5′) | functional homologue of yeast snR77 | AF357323 |
| MBII-142 | 1 | 58 | 77 | human | Cm1272 in 18S | 12 nt (5′) | AF357324 | |
| MBII-180 | 2 | 89 | 80 | human EST | Cm3670 in 28S | 10 nt (5′) | functional homologue of yeast snR76 | AF357325 |
| MBII-211 | 2 | 72 | 80 | human EST | Cm3670 in 28S | 10 nt (5′) | homologue of yeast snR76, isoform of MBII-180 | AF357326 |
| MBII-202 | 1 | 48 | 70 | human, rat | Am2378 and Um428 in 18S | 14 nt (3′) and 13 nt (5′) | intron of rpL13 gene | AF357327 |
| MBII-210 | 5 | 59 | – | human EST | Gm4454 in 28S | 9 nt (3′) | AF357328 | |
| MBII-234 | 1 | 53 | 70 | – | Am512 in 18S | 12 nt (3′) | AF357329 | |
| MBII-239 | 2 | 64 | – | human | Um14 in 5.8S | 13 nt (5′) | partial and cytoplasmic 5.8S rRNA methylation | AF357330 |
| MBII-240 | 1 | 60 | 60 | human | Um4580 in 28S | 12 nt (5′) | intron of rpL37 gene | AF357331 |
| MBII-251 | 5 | 59 | 65 | – | Gm601 in 18S | 11 nt (5′) | AF357332 | |
| MBII-276 | 3 | 64 | 72 | – | Gm3713 in 28S | 11 nt (5′) | AF357333 | |
| MBII-296 | 1 | 60 | 67 | human | Gm4578 in 28S | 16 nt (5′) | AF357334 | |
| MBII-316 | 1 | 71 | 75 | – | A3836 in 28S? | 13 nt (3′) | A3836 is not a reported methylation site | AF357335 |
| MBII-324 | 1 | 94 | 80 | – | G1630 in 28S? | 10 nt (5′) | G1630 is not a reported methylation site | AF357336 |
| MBII-333 | 1 | 82 | 75 | – | Um1670 in 18S | 9 nt (3′) | AF357337 | |
| MBII-336 | 1 | 45 | 70 | human | Am576 in 18S | 13 nt (3′) | AF357338 | |
| MBII-420 | 4 | 56 | 65 | human, rat EST | Am2764 in 28S | 12 nt (3′) | AF357339 | |
| MBII-429 | 1 | 56 | 60 | rat | Gm436 in 18S | 9 nt (5′) | intron of rpS12 gene | AF357340 |
| Group II | ||||||||
| MBII-19 | 3 | 58 | 75 | – | Cm40 in U2 | 14 nt (3′) | AF357341 | |
| MBII-119 | 1 | 62 | 75 | human EST | Cm8 in U4 | 11 nt (5′) | AF357342 | |
| MBII-166 | 11 | 98 | 105 | – | Cm60 in U6 | 13 nt (3′) | AF357343 | |
| MBII-382 | 1 | 61 | 75 | human, rat EST | Cm61 and Gm11 in U2 | 8 nt (5′) and 9 nt (5′) | AF357344 | |
| Group III | ||||||||
| MBI-46 | 1 | 249 | 280 | – | n. d. | n. d. | AF357345 | |
| MBI-52 | 1 | 73 | 110 | human | n. d. | n. d. | AF357346 | |
| MBI-106 | 1 | 63 | 120 | – | n. d. | n. d. | AF357347 | |
| MBII-4 | 1 | 67 | 100 | – | n. d. | n. d. | AF357348 | |
| MBII-115 | 27 | 99 | 105 | human EST | n. d. | n. d. | AF357349 | |
| MBII-163 | 1 | 84 | 165 | human | n. d. | n. d. | AF357350 | |
| MBII-170 | 1 | 96 | – | – | n. d. | n. d. | AF357351 | |
| MBII-244 | 1 | 68 | 120 | – | n. d. | n. d. | AF357352 | |
| MBII-289 | 1 | 93 | 100 | human EST | n. d. | n. d. | AF357353 | |
| MBII-295 | 2 | 68 | 82 | human | n. d. | n. d. | AF357354 | |
| MBII-343 | 1 | 54 | 75 | – | n. d. | n. d. | AF357355 | |
| MBII-361 | 1 | 72 | – | – | n. d. | n. d. | AF357356 | |
| MBII-366 | 1 | 56 | 85 | – | n. d. | n. d. | AF357357 | |
| MBII-419 | 1 | 28 | 56 | – | n. d. | n. d. | AF357358 | |
| MBII-426 | 1 | 30 | 60 | mouse EST | n. d. | n. d. | AF357359 |
Tables I–VI: compilation of novel ERNS from Fraction I (derived from RNAs sized 500–110 nt) and Fraction II (derived from RNAs sized 110–50 nt) cDNA libraries. ERNS: expressed RNA sequences from Fraction I (MBI-) or Fraction II (MBII-); copies: number of independent cDNA clones identified from each RNA species; cDNA: length of cDNA, as assessed by sequencing; RNA: length of RNA as assessed by northern blot analysis; homology: homology of snmRNAs to genomic or EST sequences within other organisms; modification: predicted modified nucleotides within rRNAs or snRNAs (numbering according to the human RNA sequence); antisense element: for C/D box snoRNAs, the length of the antisense element is indicated in nucleotides, followed by its location in the 5′ domain (5′) or 3′ domain (3′) of the snoRNA; location/comments: genomic locus and specific features of ERNS (when applicable); Accession No.: accession number in DDBJ/EMBL/GenBank.