Transcriptional and Post-transcriptional Regulation of pr22 (Op18) with Proliferation Control.

Abstract

ABSTRACT. The pr22 gene was isolated as a gene which is expressed in proliferating cells but not in cells which are differentiated or growth-arrested. Whencells of the human monocytic cell line, U937, were differentiated into macrophages, transcription of pr22 was almost completely suppressed. Serum starvation resulted in the inhibition of transcription, although U937failed to differentiate. In a culture synchronized with excess thymidine, mRNAofpr22 was detected at the Gl/S boundary, with the level increasing in the S phase and decreasing in the G2 phase. The gene product,pr22 protein (Pr22) was found to be identical to Opl8 as well as to a catastrophe factor. Genes homologous to pr22 were detected in the genome of mouse but not in that of yeast, or Drosophila. The 5' up-stream region of the genomicpr22 contained CpGislands but no TATAbox at its appropriate position. About 20%of cell nuclei of normal human fibroblasts were stained in a speckled manner with a monoclonal antibody for C-terminal peptide of Pr22, and these cells were found to be in phases S and G2. The mitotic apparatus was also strongly stained. By Western blot analysis, Pr22 was detected in the nuclear fraction but not in the cytoplasm. The level increased from middle S to G2 phase and remained high until the early Gl phase. N-terminal truncated Pr22 was also detected in these phases. These results suggest that Pr22 mayhave an additional role other than just functioning in association with microtubules.

Identification of cJun-responsive genes in Rat-1a cells using multiple techniques: increased expression of stathmin is necessary for cJun-mediated anchorage-independent growth

“…The proximal promoter of stathmin contains a ccaat box and several potential transcription-factor-binding sites (Melhem et al, 1991a;Hosoya et al, 1996). Our mutational analysis results suggest that stathmin promoter activity was increased mainly by two E2F sites and partly by two ATF-like sites in Rat-1a cells overexpressing cJun.…”

“…The reversible nature of the changes and the requirement of the transactiva- Hosoya et al (1996); Melhem et al (1991) n.r. et al, 1995) against the transcription factor database Transfac (Liu et al 1999) and selected the consensus sequences of AP-1 (tgactca) and ATF (tgacgtca) sites and homologous sequences with one or two base pair mismatches Location of the first base of core sequence of AP-1/ATF sites.…”

“…To construct the stathmin/Op18/pr22 promoter-luciferase reporter gene plasmid, a 1.4 kb XbaI and SacI fragment of stathmin genomic DNA consisting of 0.8 kb upstream of the transcription-initiation site and 0.6 kb of noncoding exon 1 and intron 1 from pUC-pr22 (a generous gift from Dr T Marunouchi) (Melhem et al, 1991b;Hosoya et al, 1996) was subcloned into the pGL3 basic vector. The 0.9 kb XhoI and SacI fragment containing 0.3 kb upstream of the transcriptioninitiation site was subcloned into pGL3 basic vector.…”

A Study of the Effect of Shiunko, a Traditional Chinese Herbal Medicine, on Fibroblasts and Its Implication on Wound Healing Processes

“…The collagen secretion rate of fibroblasts treated with either LR 23 or Shiunko 100 (Fig. 4) was increased by up to 125% to 130%, while the increase of collagen secretion rate of the AS-treated fibroblasts 25 was only 105%. Transforming growth factor beta (TGFb) controls the upregulation of collagen synthesis in macrophages and fibroblasts.…”

“…Interestingly, proteomic analysis of the drug effect on fibroblasts indicated that more proliferation proteins were induced by Shiunko 100 lg/mL, including IF5A-1, NME-1, PKM2, SPEE, PHB, and STMN1(our unpublished data). It was known that STMN1 is a key proliferation protein, 24,25 and it can be regarded as a typical differentiation protein marker of the cell. 26 It is worth noting that Shiunko could induce an increase in expression level of STMN1 by up to 8.5-fold (our unpublished data), indicating that STMN1 may play an important role in the proliferation rate of fibroblasts.…”