Spirulina Serine / Threonine Kinase Gene Family Cloning And Expression Analysis

Spirulina is a genera of filamentous cyanobacteria,which is proposed as an important aquaculture crop both for food and food supplement.Serine/threonine kinases(STKs)have been found in an increasing number of cyanobacteria,showing its important roles in signal transduction.This paper aims at molecular cloning and functional elucidation of a putative STK sequence in Spirulina platensis.The main results are as follows:1.Ongoing Spirulina platensis genome project offers us a wealth of information concerning the sequences and organization of STK gene family in Spirulina platensis. 33 putative STK homologues were identified in Spirulina platensis draft map.Motifs and invariant amino acids typicai in eukaryotic STKs were conserved well in these proteins.These STK proteins were classified into three major families according to their domain structures.2.Genomic library of Spirulina platensis was constructed.Using the anchor primer and degeneracy primer with genomic library as PCR template,we obtain 5'end of a putative STK gene in Spirulina platensis.3.Spirulina is often challenged with temperature stress since temperature is believed to be one of the most important limiting factors for Spirulina platensis growth in northern part of China.The expression patterns of 7 STK genes were studied by semi RT-PCR analysis under 15℃and 42℃,respectively.We find that STK2103 is activated by 42℃and we propose that STK2103 should be a signal transduction element necessary for high temperature response.This research provides a foundamental cue for further study of signal transduction system in Spirulina platensis.