Abstract:

AcSERK1 is preferentially expressed during the early stage of somatic embryogenesis in
pineapple（Ananas comosus）. In order to study its transcriptional regulation，the transcription start site and
starting characteristics of the 5′ upstream regulatory sequences were identified. The full length of its 5′
upstream regulatory sequence was isolated by hiTAIL-PCR from pineapple genomic DNA. The
transcription start site confirmed by 5′ RACE was located at 258 nt from 5′ upstream of the translation start
codon（ATG）. A plant expression vector，AcSERK1（–2 090/+258）︰︰GUS，was constructed by inserting
AcSERK1（–2 090/+258）into the plasmid vector pBI121 whose promoter CaMV 35S was replaced.
Transient expression of GUS ananlysis of the promoter activity in different tissues and organs of pineapple
was conducted. All above demostrated that the promoter of AcSERK1 turned on GUS expression only in
embryogenic cell，which is the same as its behaviour on AcSERK1.

Key words: Ananas comosus, AcSERK1, promoter, embryo-specific cell, transcription start site