Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5' start sites and the 3' ends of giant transcripts of the approximately 20-kilobase (kb)-long chicken alpha-globin gene domain were identified by reverse transcription with specific primers and by nuclease S1 mapping using cloned and sequenced restriction fragments of the domain. A transcriptional unit of approximately 17 kb was found that includes all three embryonic and adult genes of the cluster. The largest transcript initiates 8 kb upstream of the gene, within a cluster of A + T-rich sequences placed upstream of a matrix attachment point, at one of several CAA(A)T boxes framing a cluster of four TATA boxes. The 5' ends of a group of 2.5-, 5-, and 12-kb globin transcripts accumulating in avian erythroblastosis virus-transformed cells, which transcribe globin genes abortively, map to the sequence ATATATAATAA 1 kb upstream of the embryonic pi-globin gene. This sequence might correspond to a site of RNA processing or of alternative transcription initiation. Transcription of the domain ends about 2 kb downstream of the last gene of the cluster, downstream of an enhancer and immediately upstream of a CR1 repetitive element in an A + T-rich sequence that includes a matrix attachment site. These data indicate that full-domain transcripts including embryonic as well as adult alpha-globin genes exist, and that the region transcribed is framed by A + T-rich linkers and matrix attachment points.
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PMID:The chicken alpha-globin gene domain is transcribed into a 17-kilobase polycistronic RNA. 168 44

The epidermal growth factor (EGF) receptor is the functional target of the mitogen EGF and the cellular homolog of the avian erythroblastosis virus erbB oncogene product. Regulation of expression of the proto-oncogene encoding the EGF receptor can be elucidated by studying the structure and function of the gene promoter outside the confines of the cell. Previously, we reported the isolation of the human EGF receptor gene promoter. The promoter is highly GC rich, contains no TATA or CAAT box, and has multiple transcription start sites. An S1 nuclease-sensitive site has now been found 80 to 110 base pairs (bp) upstream from the major in vivo transcription initiation site. Two sets of direct repeat sequences were found in this area; both conform to the motif TCCTCCTCC. When deletion mutations were made in this region of the promoter by using either Bal 31 exonuclease or S1 nuclease, we found that in vivo activity dropped three- to fivefold, on the basis of transient-transfection analysis. Examination of nuclear protein binding to normal and mutated promoter DNAs by gel retardation analysis and DNase I footprinting revealed that two specific factors bind to the direct repeat region but cannot bind to the S1 nuclease-mutated promoter. One of the specific factors is the transcription factor Sp1. The results suggest that these nuclear trans-acting factors interact with the S1 nuclease-sensitive region of the EGF receptor gene promoter and either directly or indirectly stimulate transcription.
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PMID:Modulation of epidermal growth factor receptor proto-oncogene transcription by a promoter site sensitive to S1 nuclease. 284 30