Diversity of 7 SL RNA from the signal recognition particle of maize endosperm.
An 11 S ribonucleoprotein particle was isolated from maize endosperm and shown to be functionally and structurally equivalent to the mammalian signal recognition particle. However, unlike animal cells which apparently contain a single 7 SL RNA species, maize endosperm contains a heterogeneous population of 7 SL RNA. To investigate this diversity, we have cloned and sequenced a number of the maize endosperm 7 SL RNAs isolated from functionally active SRP preparations. Some maize 7 SL RNAs are strikingly similar, differing by single base changes or short deletions; surprisingly, others share less than 70 percent sequence homology. Despite differences in primary sequence, nearly identical secondary structures can be suggested for all maize 7 SL RNAs, consistent with a proposed functional role in protein translocation for each of these RNAs. The amount of new available sequence data enabled us to define two conserved regions of presumed functional importance: A conserved sequence -G-N-A-R- in the center of a variable region which forms a well defined stem-loop and possibly is involved in an interaction with the 19 kDa protein of the SRP. Secondly, three short nucleotide stretches located in the central domain of 7 SL RNA may form part of a dynamic RNA-switch structure.
Campos
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Departmento de Biologia Molecular y Agrobiologia, Jordi Girona Salgado, Barcelona, Spain.
Palau
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Zwieb
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D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010944:Plants / Q000235:genetics*; D012313:RNA / Q000235:genetics* / Q000302:isolation & purification; D012326:RNA Splicing; D012261:Ribonucleoproteins / Q000235:genetics* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D018271:Signal Recognition Particle; D003313:Zea mays / Q000235:genetics
D012261:Ribonucleoproteins; D018271:Signal Recognition Particle; D012313:RNA; D004247:DNA