DNA replication-dependent histone genes differ from other genes which are transcribed by RNA polymerase II in that histone genes do not contain introns and have no poly(A) tail at their 3$\sp\prime$ ends. The histone mRNAs end with a conserved stem-loop. This thesis examines the requirements involved in the process of transporting histone mRNA from the nucleus to the cytoplasm. The 3$\sp\prime$ processing signal is required for exporting histone mRNA out of the nucleus. This sequence can be replaced with a polyadenylation signal but not with U1 snRNA 3$\sp\prime$ end. This sequence may also play an important role in promoting the association of histone mRNA with polyribosomes and assist in the initiation of translation of histone mRNA. A 50KD stem-loop binding protein (SLBP) has been identified by RNA mobility shift and UV-crosslinking assays. Different complexes are formed in the nucleus and the cytoplasm with the nuclear complex being larger. The nuclear and cytoplasmic SLBP are the same proteins demonstrated by partial proteolysis. The interaction between the stem-loop RNA and SLBP is extremely sequence dependent. However none of the mutants of stem-loop has a significant effect on transport of the mRNA. Instead the mutations severely reduce the SLBP binding activity and expression of histone mRNA. These suggest that the interaction between the SLBP and stem-loop is critical for histone mRNA processing. An additional nuclear factor has also been identified which is involved in nuclear SLBP-RNA complex and is probably located on the nuclear membrane, suggesting that this factor along with SLBP may function in the process of exporting histone mRNA to the cytoplasm. The dissociation of SLBP from histone mRNA may be the initial step for degradation to take place. The SLBP is recycled after histone mRNA is degraded and return to the nucleus. A model of the functions of SLBP in the metabolism and regulation of histone mRNA is proposed. / Source: Dissertation Abstracts International, Volume: 53-03, Section: B, page: 1209. / Major Professor: William F. Marzluff. / Thesis (Ph.D.)--The Florida State University, 1992.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76637 |
| Contributors | Sun, Jianhua., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 212 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.0018 seconds