Molecular Biology and Evolution, Vol 11, 195-207, Copyright © 1994 by Society for Molecular Biology and Evolution
MC Oliveira and MA Ragan
A group IC1 intron occurs in nuclear small-subunit (18S) ribosomal RNA (SSU
rRNA) genes of the marine red alga Porphyra spiralis var. amplifolia. This
intron occurs at the same position as the self- splicing group IC1 introns
in nuclear SSU rDNAs of the fungus Pneumocystis carinii and in the green
alga Chlorella ellipsoidea and shares sequence identity with the
Pneumocystis carinii intron in domains L1, P1, P2, and L2, outside the
conserved core. Three size variants, differing in amount of sequence in L1,
exist and are differentially distributed in geographically distinct
populations. Preliminary data suggest that the largest variant can
self-splice in vitro. Short open reading frames are present but do not
correspond to known genes. Repeated nucleotide motifs, reminiscent of
duplicated target sites of transposons or Alu elements, are associated with
the intron and with one of the variant forms of L1. Insertions are present
in nuclear SSU rDNAs of several other Porphyra species and of the red alga
Bangia atropurpurea; insertionless rDNA variants also occur in several
Porphyra species. Our observations are most readily explained by intron
mobility, although it remains unclear how transfer could have been mediated
between genomes of organisms as ecologically diverse as marine red algae,
freshwater green algae, and a mammalian-pathogenic fungus.
ORIGINAL ARTICLE
Variant forms of a group I intron in nuclear small-subunit rRNA genes of the marine red alga Porphyra spiralis var. amplifolia
Instituto de Biociencias, Universidade de Sao Paulo.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
K. M. Muller, J. J. Cannone, R. R. Gutell, and R. G. Sheath A Structural and Phylogenetic Analysis of the Group IC1 Introns in the Order Bangiales (Rhodophyta) Mol. Biol. Evol., September 1, 2001; 18(9): 1654 - 1667. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. M. Muller, M. C. Oliveira, R. G. Sheath, and D. Bhattacharya Ribosomal DNA phylogeny of the Bangiophycidae (Rhodophyta) and the origin of secondary plastids Am. J. Botany, August 1, 2001; 88(8): 1390 - 1400. [Full Text] |
||||
![]() |
M. C. Oliveira and D. Bhattacharya Phylogeny of the Bangiophycidae (Rhodophyta) and the secondary endosymbiotic origin of algal plastids Am. J. Botany, April 1, 2000; 87(4): 482 - 492. [Abstract] [Full Text] |
||||

