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The polyribosomal protein bound to the 3' end of histone mRNA can function in histone pre-mRNA processing
Z Dominski1, J Sumerel, R J Hanson
1Program in Molecular Biology and Biotechnology, University of North Carolina, Chapel Hill 27599, USA.
Abstract:
Histone mRNAs end in a conserved 26 nt sequence which can form a stem-loop with a six-base stem and a four base loop. The 3' end of histone mRNA functions in the nucleus in pre-mRNA processing and mRNA transport and in the cytoplasm in translation and regulation of histone mRNA stability. The stem-loop binding protein (SLBP), found in both the polyribosomes and the nucleus, binds to the 3' end of histone mRNA. A nuclear extract which efficiently processes histone pre-mRNA has been prepared from mouse myeloma cells. The factors which bind the 3' end of histone mRNA can be depleted from this extract using a biotinylated oligonucleotide. Using the depleted extract, we show that the SLBP found in the polyribosomes can function in histone pre-mRNA processing, suggesting that the SLBP associates with histone pre-mRNA in the nucleus and accompanies the mature mRNA to the cytoplasm.
Insights
Stem-loop binding protein (SLBP) binds histone mRNA's 3' end. This protein, found in the nucleus and cytoplasm, is crucial for pre-mRNA processing and translation regulation.
Area of Science:
- Molecular Biology
- Gene Expression Regulation
Background:
- Histone mRNAs possess a conserved 3' stem-loop structure essential for their function.
- This 3' end plays critical roles in nuclear pre-mRNA processing, mRNA transport, and cytoplasmic translation and stability regulation.
- Stem-loop binding protein (SLBP) interacts with this 3' end and is present in both the nucleus and polyribosomes.
Purpose of the Study:
- To investigate the role of SLBP in histone pre-mRNA processing.
- To determine if cytoplasmic SLBP can participate in nuclear pre-mRNA processing.
- To elucidate the functional association of SLBP with histone mRNA throughout its lifecycle.
Main Methods:
- Preparation of a nuclear extract from mouse myeloma cells capable of efficient histone pre-mRNA processing.
- Depletion of 3'-end binding factors from the nuclear extract using a biotinylated oligonucleotide.
- Assay of pre-mRNA processing in the depleted extract to assess SLBP function.
Main Results:
- A nuclear extract efficiently processed histone pre-mRNA.
- Depletion of 3'-end binding factors using a biotinylated oligonucleotide was achieved.
- The SLBP present in polyribosomes demonstrated functionality in histone pre-mRNA processing within the depleted nuclear extract.
Conclusions:
- SLBP can function in the nuclear processing of histone pre-mRNA.
- The findings suggest SLBP associates with histone pre-mRNA in the nucleus.
- SLBP likely accompanies mature histone mRNA from the nucleus to the cytoplasm.