title: Topology of mRNA chain in isolated eukaryotic double-row polyribosomes.
abstract: In the process of protein synthesis, the translating ribosomes of eukaryotic cells form polyribosomes that are found to be multiplex functional complexes possessing elements of ordered spatial organization. As revealed by a number of electron microscopy studies, the predominant visible configurations of the eukaryotic polyribosomes are circles (circular polyribosomes) and two-stranded formations (so-called double-row polyribosomes). The "long" (i.e. heavy loaded) polyribosomes are usually represented by double-row structures, which can be interpreted as either topologically circular ("collapsed rings"), or topologically linear (zigzags or helices). In the present work we have analyzed the mRNA path within the eukaryotic polyribosomes, isolated from a wheat germ cell-free translation system, by integrating two approaches: the visualization of mRNA ends in polyribosomes by marking them with gold nanoparticles (3'-end) and initiating 40S subunits (5'-end), as well as by the cryoelectron tomography. Examination of the location of the mRNA markers in polyribosomes and mutual orientation of ribosomes in them has shown that the double-row polyribosomes of the same sample can have both circular and linear arrangements of their mRNA.
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
authors.forename: Zh A
authors.initials: ZhA
authors.lastname: Afonina
authors.forename: A G
authors.initials: AG
authors.lastname: Myasnikov
authors.forename: N F
authors.initials: NF
authors.lastname: Khabibullina
authors.forename: A Yu
authors.initials: AY
authors.lastname: Belorusova
authors.forename: J-F
authors.initials: JF
authors.lastname: Menetret
authors.forename: V D
authors.initials: VD
authors.lastname: Vasiliev
authors.forename: B P
authors.initials: BP
authors.lastname: Klaholz
authors.forename: V A
authors.initials: VA
authors.lastname: Shirokov
authors.forename: A S
authors.initials: AS
authors.lastname: Spirin
mesh_terms: D056890:Eukaryota / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009690:Nucleic Acid Conformation; D011132:Polyribosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D012333:RNA, Messenger