Identification And Characterization Of A Novel ZM401 Gene Family Member, ZM908

The past four years have seen an explosion in the number of detected RNA transcripts with no apparent protein-coding potential. This has led to speculation that non-protein-coding RNAs (ncRNAs) might be as important as proteins in the regulation of vital cellular functions.This study was beginning based on some positive λ phages screened from the genomic library of maize by using the labeled ZM401 cDNA fragment as probe. By subcloning, an 1822bp sequence was obtained from one of the positive λ phages .It contains 215 bp, named as ZM908. Biosoftware anlysis sug gests that ZM908 gene properly belongs to the mRNA-like non-coding RNA gene which is purposed to lack of obvious open reading frame (the longest possibly contains 98 AA), contain poly(A) tale and have stable RNA structure in vivo. ZM908 contains high conserved nucleotide sequence with ZM401 (including 371-598bp, 698-847bp and 929-1047bp in ZM908). The highest conserved sequence reaches 86%.The RT-PCR analysis result revealed that ZM908 is transcriptable. Southern hybridization indicated that maize genome probably carried only one copy of the ZM908 gene.To gain more information about the function of ZM908, we constructed sense and antisense ZM908 plant expression vector. The two vectors driven by CaMV35S promoter were introduced into tobacco and Arabidopsis, by Agrobacterium-mediated transformation, respectively. By PCR detection, 30 sense transgenic and 4 antisense transgenic tobaccos of TO generation and 14 sense transgenic and 6 antisense transgenic Arabidopsis of T2 generation are obtained. The aberrant phenotypes were observed in the tobacco transformed with ZM908 sense construct: the inflorescence growth was suppressed; the flower buds fell off and pollen grains were yellow and abnormal in the I₂-IK dye experiment, while those aberrant phenotypes were not observed in the Arabidopsis though sense transformed pollen grains were slightly sunken in the observation under scanning electronic microscope. The decrease rates of pollen germination were observed in both transgenic tobacco and Arabidopsis with ZM908 sense construct compared with the corresponding rates of non-transformed plants. However, plants transformed with antisense ZM908 vector were the same as normal. All these results concluded that the ZM908 gene, a member of ZM401 gene family, plays an important role during pollen development.