Gene expression profiling of coccolith-bearing cells and naked cells in haptophyte Pleurochrysis haptonemofera with a cDNA macroarray system.
Pleurochrysis haptonemofera is a unicellular marine coccolithophorid that has calcified scales, coccoliths, on the cell surface. Some coccolithophorids including P. haptonemofera have a coccolith-bearing stage and a naked stage in their life cycles. To characterize genes involved in the coccolithogenesis, we generated a total of 9550 expressed sequence tags (EST) from a normalized cDNA library that was prepared using both coccolith-bearing cells (C-cells) and naked cells (N-cells), constructed a cDNA macroarray using the EST clones, and then analyzed the gene expression specificity in C-cells and N-cells. When cDNA clones whose expression ratio exceeded 3-fold were selected, as many as 180 clones were identified as C-cell-specific ones, while only 12 were found to be N-cell-specific ones. These clones were sequenced, assembled, and homology-searched against a public nonredundant protein database. As a result, they were grouped into 54 C-cell-specific and 6 N-cell-specific genes, and 59% and 50% of these genes exhibited significant similarity to those of other known proteins, respectively. To assess mRNA expression further, Northern hybridization was performed for 12 of the C-cell-specific genes and one of the N-cell-specific ones. These clones, together with the new cDNA macroarray, will provide a powerful tool for the future genome-wide functional analysis of uncharacterized genes related to the regulation of the calcification and life cycle of coccolithophorids.
Fujiwara
Shoko
S
School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan. fujiwara@ls.toyaku.ac.jp
Hirokawa
Yasutaka
Y
Takatsuka
Yukiko
Y
Suda
Kunihiro
K
Asamizu
Erika
E
Takayanagi
Takatoshi
T
Shibata
Daisuke
D
Tabata
Satoshi
S
Tsuzuki
Mikio
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern / Q000662:veterinary; D016054:DNA, Protozoan / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry; D056890:Eukaryota / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling / Q000662:veterinary*; D017125:Genes, Protozoan / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000662:veterinary*; D016415:Sequence Alignment / Q000662:veterinary
D016054:DNA, Protozoan