Home About us Contact
|
Home About us Contact | ||
|
|
||
Attachment Regions (attachment + regions)
Kinds of Attachment Regions Selected AbstractsFunctional potential of P2P-R: A role in the cell cycle and cell differentiation related to its interactions with proteins that bind to matrix associated regions of DNA?JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2003Robert E. Scott Abstract P2P-R is the alternately spliced product of the P2P-R/PACT gene in that P2P-R lacks one exon encoding 34 amino acids. The 250 kDa P2P-R protein is the predominate product expressed in multiple murine cell lines. It is a highly basic protein that contains multiple domains including an N-terminal RING type zinc finger, a proline rich domain, an RS region, and a C-terminal lysine-rich domain. P2P-R binds the p53 and the Rb1 tumor suppressors and is phosphorylated by the cdc2 and SRPK1a protein kinases. P2P-R also interacts with scaffold attachment factor-B (SAF-B), a well characterized MARs (for matrix attachment regions) binding factor, and may interact with nucleolin, another MARs binding factor. In addition, P2P-R binds single strand DNA (ssDNA). The expression of P2P-R is regulated by differentiation and cell cycle events. P2P-R mRNA is markedly repressed during differentiation, whereas immunoreactive P2P-R protein levels are >10-fold higher in mitotic than in G0 cells. The localization of P2P-R also is modulated during the cell cycle. During interphase, P2P-R is present primarily in nucleoli and nuclear speckles whereas during mitosis, P2P-R associates with the periphery of chromosomes. Overexpression of near full length P2P-R induces mitotic arrest in prometaphase and mitotic apoptosis, and overexpression of selected P2P-R segments also can promote apoptosis. This compendium of data supports the possibility that P2P-R may form complexes with the Rb1 and/or p53 tumor suppressors and MARs-related factors, in a cell cycle and cell differentiation-dependent manner, to influence gene transcription/expression and nuclear organization. J. Cell. Biochem. 90: 6,12, 2003. © 2003 Wiley-Liss, Inc. [source] The characterization of versican and its message in human articular cartilage and intervertebral discJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2002Robert Sztrolovics Splicing variation of the versican message and size heterogeneity of the versican core protein were analyzed in human articular cartilage and intervertebral disc. Splicing variation of the message was studied by PCR analysis to detect the presence or absence of exons 7 and 8, which encode large chondroitin sulfate attachment regions. At all ages in normal cartilage from the third trimester fetus to the mature adult, the presence of the versican isoform possessing exon 8 but not exon 7 (V1) could be readily detected. The message isoforms possessing neither exon 7 nor 8 (V3) or both exons 7 and 8 (V0) were only detectable in the fetus, and the isoform possessing only exon 7 (V2) was never detected. In osteoarthritic cartilage and in adult intervertebral disc the versican message pattern was the same as that observed in the normal adult with only the isoform possessing exon 8 being detected. Core protein heterogeneity was studied by immunoblotting following enzymic removal of the glycosaminoglycan chains from the proteoglycan, using an antibody recognizing the globular G1 region of versican. All articular cartilage extracts from the fetus to the mature adult contained multiple core protein sizes of greater than 200 kDa. The adult cartilage extracts tended to have an increased proportion of the smaller sized core proteins and osteoarthritic cartilage possessed similar core protein sizes to the normal adult. In contrast, intervertebral disc at all post-natal ages showed a greater range of size heterogeneity with a prominent component of about 50 kDa. The abundance of this component increased if the samples were treated with keratanase prior to analysis, suggesting that the G1 region of versican in disc can be substituted with keratan sulfate. The increased presence of versican in the disc relative to articular cartilage may suggest a more pronounced functional role for this proteoglycan, particularly in the nucleus pulposus. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Structural and bioinformatic analysis of the Roman snail Cd-Metallothionein gene uncovers molecular adaptation towards plasticity in coping with multifarious environmental stressMOLECULAR ECOLOGY, Issue 11 2009MARGIT EGG Abstract Metallothioneins (MTs) are a family of multifunctional proteins involved, among others, in stress response. The Cadmium (Cd)-MT gene of the Roman snail (Helix pomatia), for example, encodes for a protein induced upon cadmium exposure. While our previous studies have demonstrated that the expressed Cd-MT isoform of Roman snails assists detoxification of cadmium, the present work focuses on the potential plasticity of this gene in response to a variety of environmental stressors playing a crucial role in the specific ecological niche of H. pomatia. Our hypothesis is based on a bioinformatic approach involving gene sequencing, structural and in silico analysis of transcription factor binding sites (TFBs), and a comparison of these features with other MT genes. Our results show that the Roman snail's Cd-MT gene not only is the largest known MT gene, but also contains , apart from the regulatory promoter region , several intronic repeat cassettes of putative TFBs suggested to be involved in environmental stress response, immune competence, and regulation of gene expression. Moreover, intronic scaffold/matrix attachment regions (S/MARs) and stress-induced duplex destabilization sites confer a high potential for epigenetic gene regulation. This suggested regulatory plasticity is also supported by physiological data showing that Cd-MT in Roman snails can be induced differentially not only after cadmium exposure, but also in response to nonmetallic environmental stressors. It is concluded that structural analysis combined with bioinformatic screening may constitute valuable tools for predicting the potential for plasticity and niche-specific adaptation of stress-responsive genes in populations living under rapidly changing environmental conditions. [source] Increasing transient expression of CAT gene in Porphyra haitanensis by Matrix attachment regions and 18S rDNA targeted homologous recombinationAQUACULTURE RESEARCH, Issue 7 2007Zhenghong Zuo Abstract To test whether matrix attachment regions (MARs) and 18S rDNA can influence CAT gene transient expression positively in the red algae Porphyra haitanensis, a targeting vector pHR-CAT containing a portion of the 18S rDNA from P. haitanensis, pMAR1-HR-CAT containing one MAR from silkworm and a portion of the 18S rDNA from P. haitanensis and pMAR2-HR-CAT containing two MARs from silkworm and a portion of the 18S rDNA from P. haitanensis were constructed. With the electroporation method, the vectors were transferred into the protoplasts from the thalli of P. haitanensis. The results showed that the expression of chloramphenicol acetyl transferase (CAT) protein in transformed cells reached a maximum at 96 h after transformation. It was increased markedly with the pMAR2-HR-CAT compared with the pHR-CAT or the pCAT@3-control vector (P<0.01), and it was increased inconspicuously with pHR-CAT compared with the pCAT@3-control vector (P>0.05). It is suggested that MAR from silkworm could enhance the transient expression of foreign genes in P. haitanensis. [source] Why repetitive DNA is essential to genome functionBIOLOGICAL REVIEWS, Issue 2 2005James A. Shapiro ABSTRACT There are clear theoretical reasons and many well-documented examples which show that repetitive DNA is essential for genome function. Generic repeated signals in the DNA are necessary to format expression of unique coding sequence files and to organise additional functions essential for genome replication and accurate transmission to progeny cells. Repetitive DNA sequence elements are also fundamental to the cooperative molecular interactions forming nucleoprotein complexes. Here, we review the surprising abundance of repetitive DNA in many genomes, describe its structural diversity, and discuss dozens of cases where the functional importance of repetitive elements has been studied in molecular detail. In particular, the fact that repeat elements serve either as initiators or boundaries for heterochromatin domains and provide a significant fraction of scaffolding/matrix attachment regions (S/MARs) suggests that the repetitive component of the genome plays a major architectonic role in higher order physical structuring. Employing an information science model, the ,functionalist' perspective on repetitive DNA leads to new ways of thinking about the systemic organisation of cellular genomes and provides several novel possibilities involving repeat elements in evolutionarily significant genome reorganisation. These ideas may facilitate the interpretation of comparisons between sequenced genomes, where the repetitive DNA component is often greater than the coding sequence component. [source] | ||||||||||