Cloning of the genes encoding two murine and human cochlear unconventional type I myosins.
Several lines of evidence indicate a crucial role for unconventional myosins in the function of the sensory hair cells of the inner ear. We report here the characterization of the cDNAs encoding two unconventional type I myosins from a mouse cochlear cDNA library. The first cDNA encodes a putative protein named Myo1c, which is likely to be the murine orthologue of the bullfrog myosin I beta and which may be involved in the gating of the mechanotransduction channel of the sensory hair cells. This myosin belongs to the group of short-tailed myosins I, with its tail ending shortly after a polybasic, TH-1-like domain. The second cDNA encodes a novel type I myosin Myo1f which displays three regions: a head domain with the conserved ATP- and actin-binding sites, a neck domain with a single IQ motif, and a tail domain with the tripartite structure initially described in protozoan myosins I. The tail of Myo1f includes (1) a TH-1 region rich in basic residues, which may interact with anionic membrane phospholipids; (2) a TH-2 proline-rich region, expected to contain an ATP-insensitive actin-binding site; and (3) a SH-3 domain found in a variety of cytoskeletal and signaling proteins. Northern blot analysis indicated that the genes encoding Myo1c and Myo1f display a widespread tissue expression in the adult mouse. Myo1c and Myo1f were mapped by in situ hybridization to the chromosomal regions 11D-11E and 17B-17C, respectively. The human orthologuous genes MYO1C and MYO1F were also characterized, and mapped to the human chromosomal regions 17p18 and 19p13.2-19p13.3, respectively.
Crozet
F
F
Unité de Génétique Moléculaire Humaine, Centre National de la Recherche Scientifique, Institut Pasteur, Paris, France.
el Amraoui
A
A
Blanchard
S
S
Lenoir
M
M
Ripoll
C
C
Vago
P
P
Hamel
C
C
Fizames
C
C
Levi-Acobas
F
F
Depétris
D
D
Mattei
M G
MG
Weil
D
D
Pujol
R
R
Petit
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003051:Cochlea / Q000737:chemistry*; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D015723:Gene Library; D005796:Genes / Q000235:genetics*; D006801:Humans; D007668:Kidney / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009218:Myosins / Q000235:genetics*; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D018076:DNA, Complementary; D012333:RNA, Messenger; D009218:Myosins