scholarly journals p68 RNA helicase: identification of a nucleolar form and cloning of related genes containing a conserved intron in yeasts.

1991 ◽  
Vol 11 (3) ◽  
pp. 1326-1333 ◽  
Author(s):  
R D Iggo ◽  
D J Jamieson ◽  
S A MacNeill ◽  
J Southgate ◽  
J McPheat ◽  
...  

The human p68 protein is an RNA-dependent ATPase and RNA helicase which was first identified because of its immunological cross-reaction with a viral RNA helicase, simian virus 40 large T antigen. It belongs to a recently discovered family of proteins (DEAD box proteins) that share extensive regions of amino acid sequence homology, are ubiquitous in living organisms, and are involved in many aspects of RNA metabolism, including splicing, translation, and ribosome assembly. We have shown by immunofluorescent microscopy that mammalian p68, which is excluded from the nucleoli during interphase, translocates to prenucleolar bodies during telophase. We have cloned 55% identical genes from both Schizosaccharomyces pombe and Saccharomyces cerevisiae and shown that they are essential in both yeasts. The human and yeast genes contain a large intron whose position has been precisely conserved. In S. cerevisiae, the intron is unusual both because of its size and because of its location near the 3' end of the gene. We discuss possible functional roles for such an unusual intron in an RNA helicase gene.

1991 ◽  
Vol 11 (3) ◽  
pp. 1326-1333
Author(s):  
R D Iggo ◽  
D J Jamieson ◽  
S A MacNeill ◽  
J Southgate ◽  
J McPheat ◽  
...  

The human p68 protein is an RNA-dependent ATPase and RNA helicase which was first identified because of its immunological cross-reaction with a viral RNA helicase, simian virus 40 large T antigen. It belongs to a recently discovered family of proteins (DEAD box proteins) that share extensive regions of amino acid sequence homology, are ubiquitous in living organisms, and are involved in many aspects of RNA metabolism, including splicing, translation, and ribosome assembly. We have shown by immunofluorescent microscopy that mammalian p68, which is excluded from the nucleoli during interphase, translocates to prenucleolar bodies during telophase. We have cloned 55% identical genes from both Schizosaccharomyces pombe and Saccharomyces cerevisiae and shown that they are essential in both yeasts. The human and yeast genes contain a large intron whose position has been precisely conserved. In S. cerevisiae, the intron is unusual both because of its size and because of its location near the 3' end of the gene. We discuss possible functional roles for such an unusual intron in an RNA helicase gene.


1999 ◽  
Vol 73 (9) ◽  
pp. 7912-7915 ◽  
Author(s):  
Mainul Hoque ◽  
Ken-ichiro Ishizu ◽  
Akiko Matsumoto ◽  
Song-Iee Han ◽  
Fumio Arisaka ◽  
...  

ABSTRACT Adeno-associated virus capsids are composed of three proteins, VP1, VP2, and VP3. Although VP1 is necessary for viral infection, it is not essential for capsid formation. The other capsid proteins, VP2 and VP3, are sufficient for capsid formation, but the functional roles of each protein are still not well understood. By analyzing a series of deletion mutants of VP2, we identified a region necessary for nuclear transfer of VP2 and found that the efficiency of nuclear localization of the capsid proteins and the efficiency of virus-like particle (VLP) formation correlated well. To confirm the importance of the nuclear localization of the capsid proteins, we fused the nuclear localization signal of simian virus 40 large T antigen to VP3 protein. We show that this fusion protein could form VLP, indicating that the VP2-specific region located on the N-terminal side of the protein is not structurally required. This finding suggests that VP3 has sufficient information for VLP formation and that VP2 is necessary only for nuclear transfer of the capsid proteins.


1982 ◽  
Vol 44 (3) ◽  
pp. 963-973 ◽  
Author(s):  
M Lovett ◽  
C E Clayton ◽  
D Murphy ◽  
P W Rigby ◽  
A E Smith ◽  
...  

1990 ◽  
Vol 64 (10) ◽  
pp. 4799-4807 ◽  
Author(s):  
A Höss ◽  
I Moarefi ◽  
K H Scheidtmann ◽  
L J Cisek ◽  
J L Corden ◽  
...  

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