The Eukaryotic Translation Initiation Factor 5, eIF-5, a Protein fromZea mays,Containing a Zinc-Finger Structure, Binds Nucleic Acids in a Zinc-Dependent Manner

1997 ◽  
Vol 236 (2) ◽  
pp. 510-516 ◽  
Author(s):  
Ignacio López Ribera ◽  
Luis Ruiz-Avila ◽  
Pere Puigdomènech
Keyword(s):  
Nucleic Acids ◽  
Zinc Finger ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation

scholarly journals hnRNP K Binds a Core Polypyrimidine Element in the Eukaryotic Translation Initiation Factor 4E (eIF4E) Promoter, and Its Regulation of eIF4E Contributes to Neoplastic Transformation

2005 ◽  
Vol 25 (15) ◽  
pp. 6436-6453 ◽  
Author(s):  
Mary Lynch ◽  
Li Chen ◽  
Michael J. Ravitz ◽  
Sapna Mehtani ◽  
Kevin Korenblat ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Binding Protein ◽  
Neoplastic Transformation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Eukaryotic Translation Initiation Factor ◽  
Hnrnp K ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation

ABSTRACT Translation initiation factor eukaryotic translation initiation factor 4E (eIF4E) plays a key role in regulation of cellular proliferation. Its effects on the m7GpppN mRNA cap are critical because overexpression of eIF4E transforms cells, and eIF4E function is rate-limiting for G1 passage. Although we identified eIF4E as a c-Myc target, little else is known about its transcriptional regulation. Previously, we described an element at position −25 (TTACCCCCCCTT) that was critical for eIF4E promoter function. Here we report that this sequence (named 4EBE, for eIF4E basal element) functions as a basal promoter element that binds hnRNP K. The 4EBE is sufficient to replace TATA sequences in a heterologous reporter construct. Interactions between 4EBE and upstream activator sites are position, distance, and sequence dependent. Using DNA affinity chromatography, we identified hnRNP K as a 4EBE-binding protein. Chromatin immunoprecipitation, siRNA interference, and hnRNP K overexpression demonstrate that hnRNP K can regulate eIF4E mRNA. Moreover, hnRNP K increased translation initiation, increased cell division, and promoted neoplastic transformation in an eIF4E-dependent manner. hnRNP K binds the TATA-binding protein, explaining how the 4EBE might replace TATA in the eIF4E promoter. hnRNP K is an unusually diverse regulator of multiple steps in growth regulation because it also directly regulates c-myc transcription, mRNA export, splicing, and translation initiation.

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