title: Plant small nuclear RNAs. II. U6 RNA and a 4.5SI-like RNA are present in plant nuclei.
abstract: Two small nuclear RNA species (U6 RNA and a 4.5SI-like RNA) not described so far for plants were detected in broad bean (Vicia faba L.) nuclei. U6 RNA is 98 nucleotides long, contains psi and methylated nucleotides and shows a surprisingly high degree of sequence homology (80%) with its rat counterpart, particularly in the middle part (a 57 nucleotide-long stretch) of the molecule, where it amounts to 98%. The 4.5SI-like RNA, similar in its structure to 4.5SI RNA detected so far only in rodent nuclei, is 94 nucleotides long, contains psi and an unidentified nucleotide and exhibits 52% overall sequence homology with rat 4.5SI RNA. A block of 20 consecutive nucleotides at the 5' end of the molecule is conserved between broad bean 4.5SI-like RNA and rat 4.5SI RNA. The presence of the two RNA polymerase III internal promoter consensus sequences in 4.5SI-like RNA suggests that it is an RNA polymerase III transcript.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000032:analysis*; D007887:Fabaceae / Q000032:analysis; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D010944:Plants / Q000032:analysis*; D010946:Plants, Medicinal; D012313:RNA / Q000235:genetics / Q000302:isolation & purification*; D012342:RNA, Small Nuclear / Q000235:genetics / Q000302:isolation & purification*; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D012342:RNA, Small Nuclear; D012313:RNA