BIOCEL 03

The inner nuclear membrane protein composition regulates essential nuclear processes including:

• All answers are correct
• gene expression
• chromosome organization
• nuclear shape
• nuclear stability

Nuclear pore complexes form an aqueous channel and regulate the nuclear membrane passage of small proteins and other water-soluble molecules into and out of the nucleus mostly by:

• diffusion
• targeting sequence (nuclear localization signal)
• specific sequence motif (positively charged amino acids lysine and arginine)
• budding and fusion of vesicles
• binding to nuclear or NE-associated proteins such as lamins

Is/are an example of imported protein(s) into the nuclear compartment from the cytosol

• All answers are correct
• Histone proteins
• RNA and DNA polymerases
• Transcriptional regulatory proteins
• RNA-processing proteins

Are viruses that rely on the transport of specific viral proteins into the host cell nucleus to perturb the anti-viral response. These viruses bypass the requirement for an adaptor protein and bind directly to transport receptors through non-classical NLSs.

• All answers are correct
• positive-sense single-stranded RNA virus (+ssRNA virus)
• negative-sense single-stranded RNA virus (-ssRNA virus)
• single-stranded reverse-transcribing RNA virus (ssRNA-RT)
• RNA viruses

The nuclear pore complexes can be divided into a symmetric and asymmetric part. NPC is built from the symmetric part ______________ nucleoporins (Nups):

• membrane-anchored, scaffold and channel
• nuclear basket and cytoplasmic filament
• channel (barrier) and membrane-anchored
• scaffold (coat and adaptor) and nuclear basket
• membrane-anchored (POMs) and cytoplasmic filament

Most proteins require ________ (known as importins and exportins) to traverse the nuclear pore.

• Karyopherins alpha and beta
• Karyopherins alpha, beta, and gamma
• Importin subunit alpha-4 and exportin alpha Q2
• Importin alpha 7 and exportin gamma 6
• TGF-β1 and IFN-γ

The known nuclear localization signal can be classified into either classical NLSs or non-classical NLSs.The classical NLSs contain one or two clusters of positively charged amino acids and can be further divided into:

• monopartite or bipartite NLSs
• lysine or cytosine NLSs
• Imp-alpha or Exp-beta NLSs
• thymine or arginine NLSs
• adenine or lysine NLSs

It is a member of the karyopherin-beta family characterized as the most extensive export receptor. Intriguingly, overexpression of this receptor has been reported in various tumor types and has been correlated with poor prognosis and resistance to therapy. In addition, it is hijacked during infection by many viruses.

• CRM1 (chromosome region maintenance 1)
• Imp-b/Kapb1
• Transportin-SR
• Actin-profilin complexes
• Histones H3 and H4

The nucleo-cytoplasmic transport process mediated by members of the karyopherin protein family requires metabolic energy and it is controlled by the small Ras-like GTPase:

• Ran system
• RonGTP
• RunGDP
• RudGEF
• All answers are correct

RNAs transcribed in the nucleus are exported via:

• Non-karyopherin heterodimer Nxf1/Nxt1
• CRM1 (chromosome region maintenance 1)
• Transportin-SR
• Ran system
• Karyopherins alpha and beta