Histone H4 mRNA levels are down-regulated by 3' RNA processing during terminal differentiation of myoblasts.
The capacity for 3' processing of the histone H4 pre-mRNA is lost following differentiation of rat L6 myoblasts to myotubes. Nuclear extracts prepared from proliferating myoblasts, but not differentiated myotubes, actively process histone H4 pre-mRNA in vitro. The activity of two factors required for 3' processing, the heat-labile factor and U7 snRNP, also changes during the differentiation period, concurrent with the loss of 3' processing activity. During myotube formation, the activity of the heat-labile factor decreases significantly while the 5' sequences of the U7 snRNA become progressively resistant to micrococcal nuclease digestion. Thus, the dramatic down-shift in histone H4 mRNA levels which occurs during myoblast differentiation is controlled at both the transcriptional and posttranscriptional level.
Larson
D E
DE
Department of Molecular Biology and Genetics, College of Biological Science, University of Guelph, Canada.
Hoffmann
I
I
Zahradka
P
P
Birnstiel
M L
ML
Sells
B H
BH
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
D006657:Histones; D012322:RNA Precursors; D012333:RNA, Messenger