Structure And Expression Analysis Of Hsp 70 Genes From Two Kinds Of Seaweeds

Enteromorpha (Ulva) prolifera, a typical species of green algae, inhabits intertidal zone. Saccharina (Laminaria) japonica, a representative species of brown algae, inhabits subtidal zone. Both seaweeds have important economic and ecological value. With global climatical changes, E. prolifera and S. japonica face various environmental stresses. Therefore it is needed to explain the mechanisms of heat shock protein in response to different stimulus, the following results were obtained:DNA sequences of hsp70 of E. prolifera were cloned and analyzed. The full length of hsp70 of E. prolifera is 4795 bp. It characterized with 6 exons and 5 introns. The upstream regulatory region (1471) contained multiple cis-acting elements, such as GC box, CAAT box, and TATA box. Under different stress conditions, mRNA transcription levels of E. prolifera were quantified by Real time-PCR (RT-PCR). In heat shock group (5-40°C), the transcription level of hsp70 at 25°C was lowest. To different salinities (0-56‰), the transcription of hsp70 could be elevated by low (0‰) and high (56‰) salinities. Under UV irradiation, hsp70 transcription reached maximum at 2.5 h. No obvious transcription changes under desiccation occurred within the 3 h, and it declined gradually after 3 h. The recombinant protein (70 kDa) was obtained through construction of in vitro expression system. Western blot indicated that the recombinant protein contained His tag, and could be useful for further analyze the binding site of HSP70. DNA sequences of hsp70 of S. japonica were cloned and analyzed. It (6682 bp) contained 4 exons and 3 introns. Of the three introns, one exceeded 1000 bp, while the rest were relatively short in length. The upstream regulatory region (1597) also contained multiple regulatory elements, such as HSE,GC box, CAAT box, TATA box and some may participate in regulation of hsp70 expression. The recombinant protein (72 kDa) was obtained based on in vitro expression of hsp70, and the expression reached maximum in 5 h and became stable afterwards.