ISOLATION AND CHARACTERIZATION OF PHASE-SPECIFIC COMPLEMENTARY DNAS FROM SPOROPHYTES AND GAMETOPHYTES OF PORPHYRA-PURPUREA (RHODOPHYTA) USING SUBTRACTED COMPLEMENTARY-DNA LIBRARIES
Qy. Liu et al., ISOLATION AND CHARACTERIZATION OF PHASE-SPECIFIC COMPLEMENTARY DNAS FROM SPOROPHYTES AND GAMETOPHYTES OF PORPHYRA-PURPUREA (RHODOPHYTA) USING SUBTRACTED COMPLEMENTARY-DNA LIBRARIES, Journal of phycology, 30(3), 1994, pp. 513-520
The red alga Porphyra purpurea (Roth) C. Agardh has a life cycle that
alternates between shell-boring, filamentous sporophytes and free-livi
ng, foliose gametophytes. The significant morphological differences be
tween these two phases suggest that many genes should be developmental
ly regulated and expressed in a phnse-specific manner. In this study,
we prepared and screened subtracted complementary DIVA (cDNA) librarie
s specific for the sporophyte and gametophyte of P. purpurea. This inv
olved the construction of cDNA libraries from each phase, followed by
the removal of common clones through subtractive hybridization. Sampli
ng of the subtracted libraries indicated that 8-10% of the recombinant
colonies in each library were specific for the appropriate phase. Of
20 putative phase-specific cDNAs selected from each subtracted library
, eight unique clones were obtained for the sporophyte and seven for t
he gametophyte. After confirming their phase-specificities by hybridiz
ation to gametophyte and sporophyte messenger RNA, these 15 phase-spec
ific cDNAs were sequenced, and the deduced amino acid sequences were u
sed to search protein databanks. Two proteins encoded by the sporophyt
e-specific cDNAs and two by the gametophyte-specific cDNAs were identi
fied by their similarity to databank entries.