Nucleic Acids Research, 1985, Vol. 13, No. 21 7729-7739
© 1985
Articles |
Correct removal by splicing of a Neurospora intron in yeast
Biochemisch Laboratorium, Vrije Universiteit de Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
Received July 12, 1985. Revised October 2, 1985. Accepted October 2, 1985.
Processing of intron-containing nuclear messenger RNAs in yeast requires an internal conserved sequence (ICS) element, UACUAAC. Similar elements (
) have been identified in sequences interrupting nuclear genes of the related ascomycete Neurospora crassa. To examine the structural splicing requirements in yeast, we constructed hybrid genes containing the intron of the Neurospora histone H3 gene and cloned them into high copy number yeast vectors. Subsequently we analyzed the RNAs transcribed in yeast from the fusion genes by Northern analysis and primer extended sequencing. It turned out that the Neurospora intron, which contains the sequence element UGCUAAC, can be removed, though very inefficiently, provided that it is located near the 5'-end of the primary transcript. This proves that an A at the second position of the ICS is no absolute requirement for splicing in yeast. In addition, the results indicate that the yeast splicing machinery is intron-position dependent.