Ⅰ. INTRODUCTIONNuclear reconstitution (nuclear assembly )was reported by several laboratories in recent years and regarded as an important advance in cell biology. In vitro nuclear assembly system provides a good mod...Ⅰ. INTRODUCTIONNuclear reconstitution (nuclear assembly )was reported by several laboratories in recent years and regarded as an important advance in cell biology. In vitro nuclear assembly system provides a good model to study the organization and function of nucleus, chromatin, nuclear envelope and nuclear matrix. Although it is too early to evaluate its significance in theory and in bioengineering, there is no doubt that the prospect in this field is inspiring.展开更多
A DNA component(referred to as new DNA structure),which has higher melting point(～ 73.5℃)and is resistant to DNase I-digestion,has suocessfully been isolated from lambda DNA Hind Ⅲtreated by cooling down quickly fo...A DNA component(referred to as new DNA structure),which has higher melting point(～ 73.5℃)and is resistant to DNase I-digestion,has suocessfully been isolated from lambda DNA Hind Ⅲtreated by cooling down quickly following thermal denaturation.Transmission electron microscope(TEM)andatomic force microscope(AFM)visualizations of the DNA molecule have shown that their lenghts fall mainly inthree regions(300 — 500 nm,750 — 1 000 nm and ～ 1 500 nm),indicating that longer fragments of λ-DNA HindⅢ are apt to form the new structure of DNA under experimental conditions;moreover,the apparent width inthe middle part of TEM imagesof a few longer molecules of the new structure of DNA is relatively thinner,wwhich may be reasonably deduced from the inhibition of DNase I(an endonuclease)binding to the new struc-ture of DNA.CD spectrum of the new structure contains a broad positive band centred at 245um anda weak negative band at 220 nm,indicating that the DNA molecule is distinctly different from all the known struc-tures of DNA.展开更多
基金This work was supported by grants from the National Natral Science Foundation of China and Doctoral Fondstion from the National Committee for Education.
文摘Ⅰ. INTRODUCTIONNuclear reconstitution (nuclear assembly )was reported by several laboratories in recent years and regarded as an important advance in cell biology. In vitro nuclear assembly system provides a good model to study the organization and function of nucleus, chromatin, nuclear envelope and nuclear matrix. Although it is too early to evaluate its significance in theory and in bioengineering, there is no doubt that the prospect in this field is inspiring.
基金the"Eighth Five-Year Plan"Proiect Grant of the CAS
文摘A DNA component(referred to as new DNA structure),which has higher melting point(～ 73.5℃)and is resistant to DNase I-digestion,has suocessfully been isolated from lambda DNA Hind Ⅲtreated by cooling down quickly following thermal denaturation.Transmission electron microscope(TEM)andatomic force microscope(AFM)visualizations of the DNA molecule have shown that their lenghts fall mainly inthree regions(300 — 500 nm,750 — 1 000 nm and ～ 1 500 nm),indicating that longer fragments of λ-DNA HindⅢ are apt to form the new structure of DNA under experimental conditions;moreover,the apparent width inthe middle part of TEM imagesof a few longer molecules of the new structure of DNA is relatively thinner,wwhich may be reasonably deduced from the inhibition of DNase I(an endonuclease)binding to the new struc-ture of DNA.CD spectrum of the new structure contains a broad positive band centred at 245um anda weak negative band at 220 nm,indicating that the DNA molecule is distinctly different from all the known struc-tures of DNA.
