Subject: Novel kinase: p38c
We have identified p38C, a third member of the p38 MAP kinase family, by
analysis of genomic sequence, using a profile HMM to detect kinase
sequences followed by genewise to extend the initial sequence by homology
and genomic walking to find start and stop sites. The protein (TrEMBL:
P83100) aligns along its full length with fly p38A (Mpk2) and p38B (53%
identity, 72-73% similarity), and also with mammalian p38 alpha-delta
(39-44% sequence identity, 62-64% similarity), suggesting that a single
ancestral p38 gene may have duplicated independently in the insect and
vertebrate lineages. C. elegans has two p38 genes (F42G8.3 and B0218.3)
which are slightly more similar to each other than to fly or human p38s,
again arguing for lineage-specific duplications.
The sequence maps as a single exon at 91E1-2; curiously p38A/Mpk2 also
consists of a single exon and maps 462bp upstream from p38C, indicating
that these may have arisen by genomic duplication. The two DNA sequences
are 61% identical in their overlap; the conservation of peptide open
reading frame despite DNA sequence divergence argues against p38C being a
pseudogene, though no ESTs have been sequenced from this gene, and the
putative promoter region is small. ESTs encoding a putative seryl tRNA
ligase start 123 bp downstream of the p38C stop, further showing crowding
of genes in this area.
\-Gerard Manning.