Sea urchin U1 genes coding for the major embryonic U1 RNA are in the tandemly repeated units. The U1 repeat unit in L. variegatus is variable in size from 1.2 to 1.4 Kb while that in S. purpuratus has a homogenous size of 1.1 Kb. Two types of U1 repeats have been isolated from L. variegatus. They are conserved in the 5$\sp\prime$ flanking region for 500 bp, but vary in the 3$\sp\prime$ flanking sequence immediately after the CAAAGAAAGAAAA sequence necessary for 3$\sp\prime$ end formation. The tandemly repeated U1 cluster of S. purpuratus ends just 3$\sp\prime$ to the U1 coding region. / The sea urchin U1 gene is transcribed by RNA polymerase II in isolated nuclei, but it can be transcribed by RNA polymerase III in sea urchin nuclear extracts. Two assays were used for testing promoter function, a microinjection assay for testing the expression of U1 genes in vivo and a DNA-dependent nuclear extract for testing expression in vitro. At least 200 nucleotides, but no more than 345 nucleotides, 5$\sp\prime$ to the gene are required for the expression of U1 gene in vivo. Two of the four highly conserved regions between L. variegatus and S. purpuratus U1 5$\sp\prime$ flanking region are in these 142 nucleotides. In contrast, none of the 5$\sp\prime$ flanking region, but rather an internal promoter region is required for the synthesis of U1 RNA by RNA polymerase III in vitro. The internal promoter region contains a tRNA A-box consensus sequence and an 11-bp region with identical sequence to one of the highly conserved regions. These data suggest that the four highly conserved regions in the 5$\sp\prime$ flanking sequence are important for the expression of the sea urchin U1 gene. / Source: Dissertation Abstracts International, Volume: 50-12, Section: B, page: 5480. / Major Professor: William F. Marzluff, Jr. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78138 |
| Contributors | Yu, Jin-Chen., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 161 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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