RRC ID 5495
Author Kijimoto-Ochiai S, Koda T, Suwama T, Matsukawa H, Fujii M, Tomobe K, Nishimura M.
Title Low expression of Neu2 sialidase in the thymus of SM/J mice-existence of neuraminidase positive cells "Neu-medullocyte" in the murine thymus.
Journal Glycoconj. J.
Abstract We have already reported that the homogenate of the A/J mouse thymus shows a high sialidase activity at the neutral pH region and that in both soluble and membrane fractions optimal pH was 6.5-7 (Kijimoto-Ochiai et al., Glycoconj. J., 20:375-384, 2004). In the present study, we investigated the level of sialidase activities in the thymus of the SM/J mouse, a mouse strain that we know to have a Neu1(a) allele that reveals a low level of sialidase activity in the liver. We found that while in the A/J thymus the soluble sialidase activity at pH 6.5 was high, the SM/J thymus lacked all such activity. A QTL analysis of SMXA recombinant inbred strains showed that soluble sialidase activity correlated well with the D1Mit8/9 marker on chromosome 1. The murine whole DNA-sequence data and the results of our FISH analysis (Kotani et al., Biochem. Biophys. Res. Comm., 286:250-258, 2001) showed that this location is consistent with the position of Neu2 gene. We confirmed that it is hard to detect the Neu2 enzyme of the SM/J mouse thymus by an anti-Neu2 antibody using a Western blot analysis. We also found that while the mRNA expression of Neu2 was quite normal in the SM/J mouse liver, it was very low in the SM/J mouse thymus. We therefore conclude that the lack of soluble sialidase activity in the SM/J mouse thymus is due to the thymus-specific low expression level of the Neu2 gene. We have previously shown that the sialidase positive cell which contains the Mac-1 and immunoglobulin, and which is located sparsely in the corticomedullar region or medullary region of the A/J mouse thymus (Kijimoto-Ochiai et al., Glycoconj. J., 20:375-384, 2004). We showed now in this paper that the detection of this cell in the SM/J mouse thymus at pH 7.0 was difficult. We propose, therefore, to name the cell "Neu-medullocyte".
Volume 25(8)
Pages 787-96
Published 2008-11
DOI 10.1007/s10719-008-9126-8
PMID 18553168
MeSH Animals Base Sequence Cell Separation DNA Primers / genetics Flow Cytometry Gene Expression In Situ Hybridization, Fluorescence Liver / enzymology Mice Mice, Inbred Strains Neuraminidase / genetics Neuraminidase / metabolism* Quantitative Trait Loci RNA, Messenger / genetics RNA, Messenger / metabolism Recombination, Genetic Solubility Thymus Gland / cytology* Thymus Gland / enzymology* Tissue Distribution
IF 2.926
Times Cited 3