Cytomegalovirus Intron A fragments
Cytomegalovirus (CMV) Intron A fragments for expressing gene products are disclosed. Also described are expression vectors including the fragments, as well as methods of using the same.
1. A human cytomegalovirus (hCMV) Intron A fragment, wherein said fragment has an internal deletion of at least 10 nucleotides of the full-length Intron A sequence and comprises: (a) the contiguous sequence of nucleotides found at positions 1-25 of SEQ ID NO: 1, and (b) the contiguous sequence of nucleotides found at positions 775-820 of SEQ ID NO: 1, wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels equal to, or greater than, those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.
2. The Intron A fragment of claim 1 , wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels at least two-fold greater than those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.
3. A recombinant expression construct effective in directing the transcription of a selected coding sequence, said expression construct comprising:
(a) a coding sequence;
(b) control elements that are operably linked to said coding sequence, wherein said control elements comprise the Intron A fragment of claim 1 ,
whereby said coding sequence can be transcribed and translated in a host cell.
4. A host cell comprising the recombinant expression construct of claim 3 .
5. The recombinant expression construct of claim 3 , wherein said control elements further comprise a promoter selected from the group consisting of a simian virus 40 (SV40) early promoter, a cytomegalovirus (CMV) promoter, a mouse mammary tumor virus long terminal repeat promoter, an adenovirus major late promoter, a rous sarcoma virus (RSV) promoter, a SRα promoter, and a herpes simplex virus promoter.
6. The Intron A fragment of claim 1 , wherein said fragment comprises: the contiguous sequence of nucleotides found at positions 1-51 of SEQ ID NO:1, and (b) the contiguous sequence of nucleotides found at positions 741-820 of SEQ ID NO:1, wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels equal to, or greater than those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.
7. The Intron A fragment of claim 6 , wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels at least two-fold greater than those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.
8. The Intron A fragment of claim 6 , wherein said fragment comprises in 5′ to 3′ order: the sequence of nucleotides 1-51 of SEQ ID NO:1, linked to nucleotides 741-820 of SEQ ID NO:1.
9. A recombinant expression construct effective in directing the transcription of a selected coding sequence, said expression construct comprising:
(a) a coding sequence;
(b) control elements that are operably linked to said coding sequence, wherein said control elements comprise the Intron A fragment of claim 8 ,
whereby said coding sequence can be transcribed and translated in a host cell.
10. A host cell comprising the recombinant expression construct of claim 9 .
11. A human cytomegalovirus (hCMV) Intron A fragment, wherein said fragment comprises the nucleotide sequence of SEQ ID NO:3, or a nucleotide sequence with at least 95% sequence identity thereto, wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels equal to, or greater than, those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.
12. The Intron A fragment of claim 11 , wherein said fragment consists of the nucleotide sequence of SEQ ID NO:3.
13. A recombinant expression construct effective in directing the transcription of a selected coding sequence, said expression construct comprising:
(a) a coding sequence;
(b) control elements that are operably linked to said coding sequence, wherein said control elements comprise the Intron A fragment of claim 12 ,
whereby said coding sequence can be transcribed and translated in a host cell.
14. A host cell comprising the recombinant expression construct of claim 13 .
15. The recombinant expression construct of claim 13 , wherein said control elements further comprise the hCMV immediate-early (IE1) enhancer/promoter region found at nucleotide positions 460 to 1264 of SEQ ID NO:4, and said control elements further comprise the sequence of nucleotides at positions 821-834 of SEQ ID NO:1.
16. A host cell comprising the recombinant expression construct of claim 15 .
17. A human cytomegalovirus (hCMV) Intron A fragment, wherein said fragment comprises in 5′ to 3′ order: a sequence of nucleotides having at least 95% sequence identity to the contiguous sequence of nucleotides found at positions 1-51 of SEQ ID NO:1 linked to a sequence of nucleotides having at least 95% sequence identity to the contiguous sequence of nucleotides found at positions 741-820 of SEQ ID NO: 1, wherein when said fragment is present in an expression construct, the expression construct directs the transcription of a coding sequence present in the construct at levels equal to, or greater than, those levels achieved by an expression construct that includes a corresponding intact, full-length Intron A sequence.