RNA-binding activity of the rat calmodulin-binding PEP-19 protein and             of the long PEP-19 isoform.
Synthesis of H1˚ histone protein, in the developing rat brain, seems to             be regulated mainly at the post-transcriptional level. Since regulation of RNA             metabolism depends on a series of RNA-binding proteins, we have been searching             for RNA-binding proteins involved in the post-transcriptional regulation of the             H1˚ gene. We recently reported isolation, from a cDNA expression library, of an             insert encoding a novel protein, the C-terminal half of which is identical to             that of PEP-19, a brain-specific protein involved in calcium metabolism. The novel             protein was called long PEP-19 isoform (LPI). Herein we show that LPI, as well             as PEP-19, can bind H1˚ RNA. Moreover, in order to improve production of functional             LPI/PEP-19, we modified the protocol normally adopted for preparing histidine             tagged-proteins from bacteria, by adding an additional purification step. We also             found that both LPI and PEP can compete for H1˚ RNA binding with PIPPin (CSD-C2),             another RNA-binding protein previously discovered in our laboratory. Since PEP19/LPI             contain a calmodulin binding domain, we finally investigated whether their ability             to bind RNA is affected by calmodulin. Our results show that calmodulin interferes             with binding of H1˚ RNA to both PEP-19 and LPI, while it is not able to bind RNA             on its own. This finding suggests that calcium/calmodulin may have a role in controlling             H1˚ mRNA metabolism in the developing brain.
Dipartimenti di Scienze e Tecnologie Molecolari e Biomolecolari, Università degli Studi di Palermo, Palermo, Italy.
Patrizia
P
Saladino
Carlo Maria
CM
Di Liegro
Patrizia
P
Proia
Anna
A
Sala
Gabriella
G
Schiera
Alessandra
A
Lo Cicero
Italia
I
Di Liegro
D000818:Animals; D001667:Binding, Competitive; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D012313:RNA / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D009419:Nerve Tissue Proteins; C489090:Pcp4 protein, rat; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D012313:RNA