Liver
Trasscription
4/9(2007)
Brain Res.
2006 Jan 5;1067(1):170-6. Epub
2005 Dec 15. Identification and
expression analysis of an actin gene from the
soft tick, Ornithodoros moubata
(Acari: Argasidae). ¡P
Horigane
M, Ogihara
K, Nakajima Y,
Honda H, Taylor D. Actin genes are found in all living
organisms and highly conserved in various animals as shown by numerous
studies on actin gene expression and function.
Because of this ubiquitous nature of actin, it is
often used as an internal control in gene expression studies. To clarify
the suitability of actin gene as an internal
control in soft ticks, isolation and expression analyses of an actin gene from Ornithodoros moubata was performed. An actin
gene of Ornithodoros moubata
(OmAct2, GenBank accession no. AB208021) with
1,131 bp and 376 amino acid residues was
identified. The homology of OmAct2 with other arthropod actin
genes was greater than 80% in nucleotides and 99% in amino acids. OmAct2
gene was classified as a cytoskeletal actin type by absence of muscle-specific amino acids
commonly found in insects and ubiquitous expression in all stages and both
sexes. Southern blot revealed that O. moubata has
four to seven actin genes. In addition, actin expression analyzed by real-time PCR before and
after blood feeding was not significantly different indicating OmAct2 is an
appropriate internal control for the analysis of gene expression in these
ticks. c 2007 Wiley-Liss,
Inc. PMID: 17366597 [PubMed - in
process] J Cell Biochem. 2007 Mar 28; [Epub
ahead of print] Nuclear actin is involved in the regulation of CSF1 gene
transcription in a chromatin required, BRG1 independent manner. ¡P
Song Z, Wang M, Wang X, Pan X, Liu W, Hao
S, Zeng
X. Institute of Genetics and
Cytology, Actin is an important protein in
nucleus and has been implicated in transcription,
however, the mechanism of its function in transcription is still not clear.
In this article, we studied the role of actin in
the regulation of human CSF1 gene transcription. Our results showed that
nuclear actin stimulates the activity of CSF1
promoter, and the role in augmenting CSF1 gene transcription requires the
formation of chromatin and Z-DNA structure. The ATP binding motifs of
nuclear actin are essential for its function in
regulating CSF1 gene transcription, and upon actin
overexpression, there is an increase in the ATPase activity of nuclear proteins. Further
investigation revealed that nuclear actin
regulates CSF1 gene transcription in a BRG1 independent manner. Together,
these original results have provided evidence for further understanding the
mechanism of nuclear actin in regulating gene
transcription. J. Cell. Biochem. (c) 2007 Wiley-Liss, Inc. PMID: 17393431 [PubMed - as
supplied by publisher] Exp
Cell Res.
2007 Apr 1;313(6):1240-50. Epub
2007 Jan 31. Regulation
of TGF-beta1/MAPK-mediated PAI-1 gene expression by the actin
cytoskeleton in human mesangial cells. ¡P
Yang C, Patel K, Harding P,
Sorokin
A, Glass WF 2nd.
Department of Pathology and
Anatomy, Eastern The importance of transforming growth factor-beta1
(TGF-beta1) in plasminogen activator inhibitor-1
(PAI-1) gene expression has been established, but the precise intracellular
mechanisms are not fully understood. Our hypothesis is that the actin cytoskeleton is involved in
TGF-beta1/MAPK-mediated PAI-1 expression in human mesangial
cells. Examination of the distributions of actin
filaments (F-actin), alpha-actinin, extracellular signal-regulated kinase
(ERK) and c-Jun N-terminal kinase (JNK) by immunofluorescence and immunoprecipitation
revealed that ERK and JNK associate with alpha-actinin
along F-actin and that TGF-beta1 stimulation
promote the dissociation of ERK and JNK with F-actin.
Disassembly of the actin cytoskeleton inhibited phosphorylation of ERK and JNK and modulated PAI-1
expression and promoter activity under both basal and TGF-beta1-stimulated
conditions. Stabilizing actin prevented dephosphorylation of ERK and JNK. ERK and JNK
inhibitors and overexpressed dominant negative
mutants antagonized the ability of TGF-beta1 to increase PAI-1 expression
and promoter activity. Disassembly of F-actin
also inhibited AP-1 DNA binding activity as determined by electrophoretic mobility shift assay using AP-1
consensus oligonucleotides derived from human
PAI-1 promoter. F-actin stabilization prevented
loss of AP-1 DNA binding activity. Therefore, changes in actin cytoskeleton modulate the ability of TGF-beta1 to
stimulate PAI-1 expression through a mechanism dependent on the activation
of MAPK/AP-1 pathways. PMID: 17328891 [PubMed - in
process]
Arch
Insect Biochem Physiol. 2007 Apr;64(4):186-99.
