Abstract Detail

Developmental and Structural Section

RUSSELL , SCOTT D [1], Jones, Daniel [1], Gou, Xiaoping [2], Bhalla, Prem [3], Singh, Mohan [4].

Transcription and incorporation of transposable element sequences in the male and female germ line of rice (Oryza sativa).

Transposable element (TE) expression presents a special challenge for the germ lineage of eukaryotic organisms, as either Type I DNA-based transposons (‘cut and paste’ with potentially disruptive indels) or Type II RNA-based retrotransposons (‘copy and paste’ multiplicative insertions) gain expression in the germ line can increase the probability of genomic alterations that could be inherited in all descendants.  Much attention has therefore been addressed to effective TE suppression, given the dangers of TE activation in the germ line.  Microarray and RNA-Seq data in pollen and sperm cells of rice, however, indicate TE signatures occurring preferentially in the germ line, with evidence of their historical incorporation.  Numerous male germ lineage transcripts correspond to promiscuous Affymetrix rice probe set sequences (those mapping multiply to sequences throughout the genome) that retain TE signature regions recognized by RepeatMasker and RetrOryza and appear to remain highly expressed.  Significant amounts of TE transcription and historical sequence insertion was also evident on occasion in egg cells, but in far lower intensity.  Incorporated sequences have diverged over time from their original functional conformations and thus these insertions appear to have had a long history, with some homologous sequences still recognized in modern day sperm cells.  Thus, rice gametes display contrasting profiles of putative TE transcription, with gender distinct patterns of expression.  Affymetrix probes sets encoding such genes often are highly expressed in the germ lineage, particularly in sperm cells and often corresponding to insertion of TE-related probe sequences with multiple insertions into loci, introns and intergenic sites throughout the rice genome.  Such sequences point to a potential paradox of apparently high expression of TE sequences with corresponding evidence of relictual past mobile element activation.

1 - University Of Oklahoma, Department Of Microbiology And Plant Biology, 770 Van Vleet Oval, Norman, OK, 73019-6155, USA
2 - Lanzhou University, School of Life Sciences, Lanzhou, Ganzu, 730000, China
3 - Uinversity of Melbourne, Melbourne School of Land and Environment, Parkville, VIC, 3010, Australia
4 - University of Oklahoma, Department of Microbiology and Plant Biology, 770 Van Vleet Oval, Norman, OK, 73019, USA

Keywords:
transposable element
Oryza
male gametophyte
female gametophyte
pollen.

Presentation Type: Oral Paper:Papers for Sections
Session: 25
Location: Pines North/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 11:45 AM
Number: 25007
Abstract ID:928
Candidate for Awards:None