|
|
|
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
|
Fig. 4. Sequence conservation and heterogeneous transcription initiation of the
Brn1 gene. (A) Conservation of the 5' flanking sequences of
mammalian and fish Brn1 genes. The PipMaker program
(Schwartz et al., 2000) was
used to compare the 10 kb upstream regions of the human and mouse
Brn1 genes. Sequence block with 50% to 100% identical sequence
(y-axis) are indicated together with their position (x-axis)
relative to the translation start codon of Brn1. The conserved
elements A,B,C,D and P share 93.2% (D) to 96.5% (B) sequence identity in the
two mammalian species (Fig. 6D;
see Fig. S1 in the supplementary material). Four of these regions (B, C, D and
P) are even conserved between mammals and the pufferfish Fugu
rubripes (shown in green). CpG islands with an average GC content of
60% are present in the first 3.8 kb upstream of the Brn1 start
codon. (B) Mapping of the transcription initiation region. 5'-RACE
amplified PCR fragments of 325 bp from E10.5 head RNA with a primer
located downstream of element P (–1098/–1069 relative to start
codon). The presence or absence of reverse transcriptase (RT) and the PCR
cycles are indicated. (C) Identification of transcription start sites.
Sequencing of the 5'-RACE products identified heterogeneous
transcriptional start sites within a 17 bp sequence of element P. The number
of PCR clones with an identical 5' end is indicated together with the
nucleotide positions relative to the start codon.
|
