High impact information on Mtap7

• Consistent with a possible role for E-MAP-115 in stabilizing microtubules, microtubule associations in the mutant were morphologically abnormal in the manchette of spermatids and in Sertoli cells [1].
• We hypothesize that the abnormal microtubules in these two cell types are responsible for deformation of spermatid nuclei and germ cell loss, respectively, and indicate an essential role for E-MAP-115 in microtubule functions required for spermatogenesis [1].
• We identified the gene encoding E-MAP-115 (epithelial microtubule-associated protein of 115 kD) as a retinoic acid-inducible gene using gene trap mutagenesis in mouse embryonic stem cells [1].
• We therefore believe that MAP7 may enhance the membrane expression of TRPV4 and possibly link cytoskeletal microfilaments [2].
• We employed 5' RACE to isolate the 5' end of the fusion transcript and this sequence was localized to the proximal end of chromosome 10 between markers Cni-rs2 and Mtap7 [3].

Biological context of Mtap7

• The distribution of murine 115-kDa epithelial microtubule-associated protein (E-MAP-115) during embryogenesis and in adult organs suggests a role in epithelial polarization and differentiation [4].
• Analysis of the predicted amino acid sequence of murine E-MAP-115 revealed 81% sequence identity with its human homolog, the best-conserved part of the protein being the microtubule-binding site [4].

Anatomical context of Mtap7

• The gene trap insertion led to a null allele of the E-MAP-115 gene and, in agreement with its high expression in the testis, male mice homozygous for the mutation were sterile because of deformation of spermatid nuclei and subsequent gradual loss of germ cells [1].
• In adult organs, E-MAP-115 is most abundant in epithelial cells of kidney tubules, in absorptive cells of the intestine and is widely distributed in the testis [4].
• The 115-kDa epithelial MAP (E-MAP-115) has been identified as a microtubule-stabilizing protein predominantly expressed in cell lines of epithelial origin [4].
• Taken together, our results provide support for a role of E-MAP-115 in reorganizing the microtubule cytoskeleton during epithelial cell polarization and differentiation [4].
• In the developing kidney, E-MAP-115 mRNA is detected in the cuboidal cells of S-shaped bodies, of primitive tubules and glomerula, whereas, E-MAP-115 mRNA and protein are absent from mature podocytes which have lost their initial apico-basal polarity [4].

References