Kyeong Won Lee , Young Jun An , Janet Lee , Ye-Eun Jung , In Young Ko , Jonghwa Jin , Ji Hoon Park , Won Kyu Lee , Kiweon Cha , Sun-Shin Cha , Jung-Hyun Lee , Hyung-Soon Yim
J. Microbiol. 2022;60(11):1086-1094. Published online November 1, 2022
Fibroblast growth factor 11 (FGF11) is one of intracrine FGFs
(iFGFs), which function within cells. Unlike canonical FGFs,
FGF11 remains intracellularly and plays biological roles in
FGF receptor (FGFR)-independent manner. Here, we established
an expression system of recombinant FGF11 proteins
in E. coli and investigated whether the extracellular administration
of FGF11 can activate cellular signaling. Human
FGF11 has two isoforms, FGF11a and FGF11b, depending
on the presence of nuclear localization sequences (NLSs) in
the N-terminus. Because these two isoforms are unstable, we
prepared an FGF11a-Mut by substituting three cysteine residues
in the NLS with serine and FGF11b-ΔC with C-terminal
truncation. The introduction of mutation in the NLS improved
the solubility of FGF11 prepared from E. coli. Exogenous
addition of FGF11b and FGF11b-ΔC to BALB3T3
increased cell proliferation, while FGF11a-Mut exerted no
effect. FGF11b-ΔC showed higher cell proliferation activity
and FGFR signaling than FGF11b. The cell-proliferating activities
of FGF11b and FGF11b-ΔC were blocked by an FGFR1
inhibitor or a recombinant FGFR1, confirming the FGFR1-
dependent extracellular activity of FGF11b. The analysis of
circular dichroism suggested that the C-terminus of FGF11
has an α-helical structure, which may affect its interaction
with FGFR1. These results suggest that the N-and C-terminus
of recombinant FGF11 are involved in the activation of
FGFR1. The above results provide novel insights into the function
and mechanism of FGF11 that may aid the development
of useful ligands for FGFR regulation.
Two novel Gram-positive, non-spore-forming, facultatively
anaerobic, non-motile, and short rods to coccoid strains were
isolated from the feces of the greater white-fronted geese
(Anser albifrons) at Poyang Lake. The 16S rRNA gene sequences
of strains 4H37-19T and 3HC-13 shared highest identity
to that of Corynebacterium uropygiale Iso10T (97.8%).
Phylogenetic and phylogenomic analyses indicated that strains
4H37-19T and 3HC-13 formed an independent clade within
genus Corynebacterium and clustered with Corynebacterium
uropygiale Iso10T. The average nucleotide identity and digital
DNA-DNA hybridization value between strains 4H37-19T and
3HC-13 and members within genus Corynebacterium were
all below 95% and 70%, respectively. The genomic G + C content
of strains 4H37-19T and 3HC-13 was 52.5%. Diphosphatidylglycerol
(DPG), phosphatidylglycerol (PG), phosphatidylinositol
(PI), phosphatidylcholine, and phosphatidyl inositol
mannosides (PIM) were the major polar lipids, with
C18:1ω9c, C16:0, and C18:0 as the major fatty acids, and MK-8
(H4), MK-8(H2), and MK-9(H2) as the predominant respiratory
quinones. The major whole cell sugar was arabinose,
and the cell wall included mycolic acids. The cell wall peptidoglycan
contained meso-diaminopimelic acid (meso-DAP).
The polyphasic taxonomic data shows that these two strains
represent a novel species of the genus Corynebacterium, for
which the name Corynebacterium poyangense sp. nov. is
proposed. The type strain of Corynebacterium poyangense
is 4H37-19T (=GDMCC 1.1738T = KACC 21671T).