|
|
Virus translocation from cytoplasm to the cell nucleus
Išler, Lukáš ; Forstová, Jitka (advisor) ; Přikryl, David (referee)
Replication cycles of most DNA and some RNA viruses require translocation of these viruses into the host cell nucleus. In this step viruses must cross the nuclear membrane. In the cell cycle interphase, it can be exceeded only by passing through nuclear pores. Individual virus families have developed different strategies to efficiently translocate through the nuclear pore. In this paper, summarizing the knowledge of viral penetration through the nuclear pore, it is shown that in addition to the interaction with transport receptors, viral particles interact directly with some proteins of the nuclear pore complex, called nucleoporins (NUPs). Especially, one group of nucleoporins, so-called FG NUPs, interacts with viral particles. Their sequence contains naturally disordered domains rich in phenylalanine-glycine (FG) repeats which create selective barrier of the nuclear pore complex. These are mainly nucleoporins NUP153, NUP214 and NUP358. Interaction of viral particles with these nucleoporins allow them to cross this barrier and deliver their viral genome to the host cell nucleus. It is therefore an essential step in the early phase of the viral infection cycle. Keywords: cell nucleus, nuclear transport, nuclear pore complex, nucleoporins, virus nuclear entry, NUP153, NUP214, NUP358
|
|
|
Role of importins in reproduction
Mertová, Irem ; Frolíková, Michaela (advisor) ; Bubeníčková, Filipa (referee)
Importins are proteins from a group of karyopherins, which provide transport of proteins into the nucleus both in somatic cells and gametes. Transport of specific transcription factors plays an important role in gametes and affects key events of reproduction. In mammals, reproduction is mediated by the process of sexual reproduction. In this event, a haploid gamete is formed in each parent, which in later stages of fertilization combine and make a diploid zygote. Gene expression in gametes differs dramatically from somatic cells. In gametes, translation is suspended and specific proteins are expressed only at certain stages of cell development. Proteins determined for transport into the nucleus contain various nuclear localization signals, which are detected by different types of importins. Based on studying differences in expression of individual types of importins in various phases of gametogenesis, we can deduce their roles in these processes. Role of importins was proven in gametogenesis, differentiation of stem cells and maturation of germ cells. On top of that, importins appear to play a role in defense of male germ cells against oxidative stress.
|
guest ::
