Phosphomannomutases: catalyze the reversible conversion of mannose 6-phosph
ate to mannose 1-phosphate. In humans, two different isozymes have recently
been identified, PMM1 and PMM2. We have previously shown that mutations in
the PMM2 gene cause the most frequent type of the congenital disorders of
glycosylation, CDG-Ia. Here, we present data on the two mouse orthologous g
enes, Pmm1 and Pmm2. The chromosomal localization of the two mouse genes ha
s been determined. We also present the gene structure and the exon-intron o
rganization of Pmm1 and Pmm2. Pmm1 maps to mouse chromosome 15, Pmm2 to chr
omosome 16. These chromosomal regions are syntenic with regions on human ch
romosomes 22 and 16, respectively. The Pmm1 gene is composed of eight exons
and spans approximately 9.5 kb. The genomic structure is extremely well co
nserved between the human and mouse gene. The Pmm2 gene consists of eight e
xons acid spans a larger genomic region (approximate to 20 kb). An alignmen
t of the human and mouse protein sequences confirms the conservation among
this family of phosphomannomutases. The two mouse genes are expressed in ma
ny tissues, but the expression pattern is slightly different between Pmm1 a
nd Pmm2. The most striking difference is the high expression of Pmm1 in bra
in tissue. whereas Pmm2 is only weakly expressed in this tissue. (C) 2001 E
lsevier Science B.V. All rights reserved.