Unusual misregulation of RNA splicing caused by insertion of a transposable element into the T (Brachyury) locus

Table 2 Sequence analysis of RT-PCR products fromT +/+,T^Wis/+, and T^Wis/T^Wisembryos. RT-PCR products are named as described in Figures 2 and 3. Products of indicated size were sequenced and compared toT mRNA sequence and genomic structure (Herrmann, Labeit et al. 1990; Genbank accession number NM-009309 [10]). Transcript sequence indicates exonic organization of RT-PCR products.

RT-PCR product	Embryo Genotype	Product Size (in bp)	Transcript sequence¹
F1-R1a	+/+	~300	6,7,8 (wild type)
F1-R1b	T^Wis/T^Wis	~300	6,7Δ35,8 & 6,7Δ35,+37ETn,8
F1-R1c	T^Wis/T^Wis	~190	6,8
F2-R1a	+/+	~480	4,5,6,7,8 (wild type)
F2-R1b	T^Wis/T^Wis	~480	4,5,6,7Δ35,8 & 4,5,6,7Δ35,+37ETn,8
F2-R1c	T^Wis/T^Wis	~220	4,5,8l
F2-R1d	T^Wis/T^Wiss	~180	4,8
F1–BGH037a	T^Wis/T^Wis	~220	6,7+Etn
F3-R1a	+/+	~160	7,8 (wild type)
F3-R1b	T^Wis/T^Wis	~200	7+60Etn,8 & 7+60ETn,+37ETn,8

¹ A comma (,) denotes the joining by splicing of non-adjacent sequences. 7Δ35 indicates an incomplete exon 7 with a 35 nucleotide deletion at the 3' end. 7+ETn and 7+60ETn indicate read-through transcription from an intact exon 7 into adjacent ETn sequences. The +37ETn mini-exon sequence is Genbank accession #Y17106 bases 4515–4479, 5'-GAAACTCAGAAATGGTCAAGCTGGACCTTCCCTTGCA-3'. The +60ETn read-through sequence is 5'-GTGTTGCGGCCGCCAGCAGCTCGCAACGTGA-ACGGTTCGACTGAGAAGGCCGCTCGAGCT-3', where the 5' most G is the first base of T intron 7 [10], and the remainder of the sequence is Genbank accession #Y17106 bases 5542–5484.

ISSN: 1471-2164