Hel-BSSS53-z1C1 on maize chromosme 4S. A) A physical map of Hel-BSSS53-z1C1 is presented. Putative genes are shown as pentagons pointing in the direction of transcription. Exons are shown in red and introns in yellow. Conserved nucleotides at the 5'-TCT and 3'-CTAG termini and 5'-a, 3'-t target sites are highlighted at the ends. B) Termini of the maize Helitrons Hel-BSSS53-z1C1 from BSSS53 4S , HelA-1a and HelB from McC 9S , Mo17_14577 from Mo17 9L, B73_14578 from B73 6S , the Helitron insertions in mutants sh2-7527  and ba1-Ref [25, 49]. Helitron sequences are in uppercase letters and the invariant host nucleotides, where the Helitrons inserted, are in italic lowercase letters. Conserved nucleotides at the 5' and 3' termini are in red bold uppercase letters and inverted repeats at the 3' termini are underlined.