Identification of altered DNA-protein interactions at the lamin A proximal promoter in quiescent hepatocytes.
The nuclear lamina of differentiated cells is composed of A-type and B-type lamins. The expression of the A-type lamins has been shown to be primarily under transcriptional control in proliferating cells. In order to gain insights into the factors involved in downregulation of the promoter in quiescent cells, we have compared the DNA-protein interactions at the rat lamin A proximal promoter in fetal (dividing) hepatocytes and adult (quiescent) hepatocytes by DNase I footprinting analysis, electrophoretic mobility shift assays and UV crosslinking experiments. We have identified proteins from adult hepatocyte nuclear extracts that are bound to sequences within 28 bp downstream of the transcription initiation site (62 and 48 kDa proteins) and within 20 bp upstream of the initiation site (54 kDa protein), which may function as transcriptional repressors of the lamin A proximal promoter.
Tiwari
B
B
Centre for Cellular and Molecular Biology, Hyderabad, India.
Parnaik
V K
VK
D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000235:genetics; D005333:Fetus; D034904:Lamin Type A; D034882:Lamins; D008099:Liver / Q000166:cytology* / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor; D014157:Transcription Factors / Q000378:metabolism
D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D004268:DNA-Binding Proteins; D034904:Lamin Type A; D034882:Lamins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D051705:Sp3 Transcription Factor; D004247:DNA; D003850:Deoxyribonuclease I