Zea mays Transcriptome or Gene expression. Zea mays

Natural Antisense Transcripts (NATs) can regulate gene expression by virtue of their ability to form double-stranded RNA duplexes. To investigate NATs in the maize transcriptome, cDNAs from seedling of two inbred lines (B73 and Mo17) were hybridized to an oligonucleotide microarray designed to validate the expression of in silico detected NATs and to screen for NATs that can anneal to a random set of 3’ UTRs and selected repeats found in 3’ UTRs regions. Quantitative Real-Time PCR experiments were conducted to determine the minimum detection threshold of microarray experiment and to thereby identify genes for which both sense and antisense transcripts accumulate to detectable levels. Two independent approaches, strand-specific RT-PCR and S1 nuclease assays were conducted to validate the results of the microarray experiment. Based on these conservative assays, NATs accumulate in seedlings that can anneal to over 70% of a random set of maize genes. In addition, both sense and antisense transcripts anneal to more than 80% of a set of maize repeats. Significantly, sense and antisense transcripts exhibit significant different expression patterns between the two genotypes. Based on these findings we hypothesize that interactions between sense and antisense transcripts may contribute to the differential patterns of gene expression in maize hybrids and to heterosis. Keywords: Global antisense transcripts profiling between two maize inbreds Overall design: To systematically identify NATs in maize, we employed multiple strategies to computationally identify putative antisense transcripts from our partial genome assembly (MAGIs) and a collection of ESTs we sequenced with known sequence orientation. Additionally, we randomly sampled and surveyed maize UTRs which often harbor transposons. Strand-specific oligonucleotides which can hybridize to the antisense strand were designed and spotted with together with the oligonucleotides hybridizing sense strands on a custom, strand-specific oligoarray, providing the first global expression profiling study of NATs in maize UTRs. In total, 10 biological replication were conducted to compare the global gene expression profiles between two maize genotypes (B73 and Mo17).