1. A mixing circuit comprising:
a balun that converts a single-ended radio-frequency signal into differential signals;
a differential matching circuit that
outputs a maximum-level positive-phase output signal of the balun at a low frequency lower than a center frequency of the radio-frequency signal and outputs a maximum-level reverse-phase output signal of the balun at a high frequency higher than the center frequency of the radio-frequency signal; or
outputs a maximum-level positive-phase output signal of the balun at a high frequency higher than the center frequency of the radio-frequency signal and outputs a maximum-level reverse-phase output signal of the balun at a low frequency lower than the center frequency of the radio-frequency signal;
an amplification circuit that amplifies a positive-phase output signal and a reverse-phase output signal of the differential matching circuit; and
a mixing circuit that converts the positive-phase output signal and the reverse-phase output signal of the amplification circuit into intermediate-frequency signals using locally generated signals.
2. The mixing circuit according to claim 1, wherein the differential matching circuit comprises:
a first inductor and at least one first variable capacitor which are connected to each other in parallel and are provided between a signal path of the positive-phase output signal of the balun and a ground; and
a second inductor and at least one second variable capacitor which are connected to each other in parallel and are provided between a signal path of the reverse-phase output signal of the balun and the ground.
3. The mixing circuit according to claim 1, wherein the differential matching circuit comprises:
a third inductor and plural series connections of a capacitor and a switch which are connected to each other in parallel and are provided between a signal path of the positive-phase output signal of the balun and a ground; and
a fourth inductor and plural series connections of a capacitor and a switch which are connected to each other in parallel and are provided between a signal path of the reverse-phase output signal of the balun and the ground.
4. The mixing circuit according to claim 1, wherein the differential matching circuit comprises:
plural capacitors which are connected to each other in series and are provided between signal paths of the positive-phase output signal and the reverse-phase output signal of the balun;
a pair of inductors provided between the signal paths of the positive-phase output signal and the reverse-phase output signal of the balun and a ground; and
switches for grounding respective connecting points of the capacitors.
5. The mixing circuit according to claim 1, wherein:
the balun is a transformer in which a grounded primary inductor and a series connection of plural secondary inductors provided between signal paths of the positive-phase output signal and the reverse-phase output signal are coupled to each other inductively;
the differential matching circuit comprises a pair of capacitors provided between the signal paths of the positive-phase output signal and the reverse-phase output signal of the balun and a ground; and
connecting points of the secondary inductors are to be grounded via respective switches.
6. The mixing circuit according to claim 1, further comprising an inductor circuit which is provided between the amplification circuit and the mixing circuit and comprises a first inductor which is series-connected to a signal path of the positive-phase output signal of the amplification circuit and a second inductor which is series-connected to a signal path of the reverse-phase output signal of the amplification circuit.
7. The mixing circuit according to claim 1, wherein:
the differential matching circuit comprises:
a first variable inductor or a first variable capacitor which adjusts frequency components of a positive-phase output signal; and
a second variable inductor or a second variable capacitor which adjusts frequency components of a reverse-phase output signal;
the amplification circuit comprises a first inductor which adjusts frequency components of a positive-phase output signal and a second inductor which adjusts frequency components of a reverse-phase output signal;
frequency components of the positive-phase output signal that is output from the amplification circuit are is adjusted using the first variable inductor or the first variable capacitor and the first inductor; and
frequency components of the reverse-phase output signal that is output from the amplification circuit are adjusted using the second variable inductor or the second variable capacitor and the second inductor.
8. The mixing circuit according to claim 1, wherein:
the amplification circuit comprises a first amplification element that amplifies the positive-phase output signal of the differential matching circuit and a second amplification element that amplifies the reverse-phase output signal of the differential matching circuit; and
the first and second amplification elements amplify the positive-phase output signal and the reverse-phase output signal of the differential matching circuit according to first and second gate bias voltages, respectively, which are supplied in synchronism with a control signal for switching the center frequency of the radio-frequency signal in the differential matching circuit.
9. A mixing circuit comprising:
a single-ended matching circuit that outputs a maximum-level single-ended radio-frequency signal at a center frequency of the radio-frequency signal;
a balun that converts the output single-ended signal of the single-ended matching circuit into differential signals;
a differential matching circuit that outputs a maximum-level positive-phase output signal of the balun at a frequency lower than or higher than the center frequency of the radio-frequency signal and outputs a maximum-level reverse-phase output signal at a frequency higher than or lower than the center frequency of the radio-frequency signal;
an amplification circuit that amplifies a positive-phase output signal and a reverse-phase output signal of the differential matching circuit; and
a mixing circuit that converts the positive-phase output signal and the reverse-phase output signal of the amplification circuit into intermediate-frequency signals using locally generated signals,
wherein the single-ended matching circuit comprises plural series connections of a capacitor and a switch which are provided between a signal path of the single-ended radio-frequency signal and a ground.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-42. (canceled)
43. A nucleic acid molecule selected from a group consisting of
i) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
ii) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
iii) nucleic acid molecules consisting of the sequence of SEQ ID NO:1,
iv) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (i), (ii), or (iii); and
v) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (iii) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity.
44. A purified polypeptide selected from a group consisting of
i) a polypeptide consisting of SEQ ID NO:2,
ii) a polypeptide comprising the sequence of SEQ ID NO:2,
iii) polypeptides encoded by nucleic acid molecules of claim 43; and
iv) polypeptides which show at least 99%, 98%, 95%, 90%, or 80% homology with a polypeptide of (i), (ii), or (iii);
wherein the purified polypeptide has MGAT-X1 activity.
45. A vector comprising the nucleic acid molecule of claim 52.
46. A host cell containing a vector comprising the nucleic acid molecule of claim 52.
47. A method of producing a MGAT-X1, comprising:
i) culturing a host cell comprising a vector which comprises the nucleic acid molecule of claim 52 under suitable conditions; and
ii) recovering the MGAT-X1 from the culture medium.
48. A method for the detection of a nucleic acid molecule encoding a MGAT-X1 in a sample, comprising:
i) hybridizing a nucleic acid molecule to nucleic acid material of the sample, thereby forming a hybridization complex, wherein the nucleic acid molecule is selected from a group consisting of
a) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
b) nucleic acid molecules comprising the sequence of SEQ ID NO: 1,
c) nucleic acid molecules having the sequence of SEQ ID NO:1,
d) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (a), (b), or (c); and
e) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (c) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity; and
ii) detecting the hybridization complex.
49. The method of claim 48 further comprising amplification of the nucleic acid material.
50. A method for the detection of a nucleic acid molecule, comprising:
i) contacting a sample with a reagent which specifically interacts with a nucleic acid molecule selected from a group consisting of
a) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
b) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
c) nucleic acid molecules having the sequence of SEQ ID NO:1,
d) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (a), (b), or (c); and
e) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (c) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity; and
ii) detecting an interaction between the reagent and the nucleic acid molecule.
51. A method for the detection of a polypeptide, comprising:
i) contacting a sample with a reagent which specifically interacts with a polypeptide selected from a group consisting of
a) a polypeptide consisting of SEQ ID NO:2,
b) a polypeptide comprising the sequence of SEQ ID NO:2,
c) polypeptides encoded by nucleic acid molecules of claim 43; and
d) polypeptides which show at least 99%, 98%, 95%, 90%, or 80% homology with a polypeptide of (a), (b), or (c);
wherein the polypeptide has MGAT-X1 activity; and
ii) detecting an interaction between the reagent and the polypeptide.
52. A method for screening for regulators of the activity of a MGAT-X1, comprising:
i) contacting a test compound with a polypeptide selected from a group consisting of:
a) a polypeptide consisting of SEQ ID NO:2,
b) a polypeptide comprising the sequence of SEQ ID NO:2,
c) polypeptides encoded by nucleic acid molecules of claim 43; and
d) polypeptides which show at least 99%, 98%, 95%, 90%, or 80% homology with a polypeptide of (a), (b), or (c);
wherein the polypeptide has MGAT-X1 activity; and
ii) detecting binding of the test compound to the polypeptide, wherein a test compound that binds to the polypeptide is identified as a potential regulator of MGAT-X1 activity.
53. The method of claim 52, wherein the step of contacting is in or at the surface of a cell.
54. The method of claim 53 wherein the cell is in vitro.
55. The method of claim 52 wherein the step of contacting is in a cell-free system.
56. The method of claim 52 wherein the polypeptide is coupled to a detectable label.
57. The method of claim 52, wherein the compound is coupled to a detectable label.
58. The method of claim 52, wherein the test compound displaces a ligand which is bound to the polypeptide.
59. The method of claim 52, wherein the polypeptide is attached to a solid support.
60. The method of claim 52, wherein the compound is attached a solid support.
61. A method of screening for regulators of the activity of a MGAT-X1, comprising:
i) measuring the activity of a polypeptide at a certain concentration of a test compound or in the absence of the test compound, wherein the polypeptide is selected from a group consisting of:
a) a polypeptide consisting of SEQ ID NO:2,
b) a polypeptide comprising the sequence of SEQ ID NO:2,
c) polypeptides encoded by nucleic acid molecules of claim 43; and
d) polypeptides which show at least 99%, 98%, 95%, 90%, or 80% homology with a polypeptide of (a), (b), or (c);
wherein the polypeptide has MGAT-X1 activity; and
ii) measuring the activity of the polypeptide at a different concentration of the test compound,
wherein the test compound is identified as a regulator of the activity of a MGAT-X1 when there is a significant difference between the activities measured in (i) and (ii).
62. The method of claim 61 wherein the activities are measured in a cell.
63. The method of claim 62 wherein the cell is in vitro.
64. The method of claim 61 wherein the activities are measured in a cell-free system.
65. A method of screening for regulators of MGAT-X1, comprising:
i) contacting a test compound with a nucleic acid molecule selected from a group consisting of
a) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
b) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
c) nucleic acid molecules having the sequence of SEQ ID NO:1,
d) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (a), (b), or (c); and
e) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (c) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity; and
ii) detecting binding of the test compound to the nucleic acid molecule,
wherein the test compound is identified as a potential regulator of MGAT-X1 when it binds to the nucleic acid molecule.
66. The method of claim 65 wherein the nucleic acid molecule is RNA.
67. The method of claim 65 wherein the contacting step is in or at the surface of a cell.
68. The method of claim 65 wherein the contacting step is in a cell-free system.
69. The method of claim 65 wherein the polypeptide or nucleic acid molecule is coupled to a detectable label.
70. The method of claim 65 wherein the test compound is coupled to a detectable label.
71. A method of diagnosing an MGAT-X1 related disease in a diseased mammal, comprising:
i) measuring the amount of a nucleic acid molecule in a sample taken from the diseased mammal, wherein the nucleic acid molecule is selected from a group consisting of
a) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
b) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
c) nucleic acid molecules having the sequence of SEQ ID NO:1,
d) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (a), (b), or (c); and
e) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (c) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity; and
ii) comparing the result of (i) to the amount of the nucleic acid molecule in at least one healthy mammal,
wherein a MGAT-X1 related disease is diagnosed in the diseased mammal when the amount of the nucleic acid molecule in the diseased mammal is significantly different from the amount of the nucleic acid molecule in the at least one healthy mammal.
72. A pharmaceutical composition comprising a nucleic acid molecule selected from the group consisting of:
i) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
ii) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
iii) nucleic acid molecules having the sequence of SEQ ID NO:1,
iv) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (i), (ii), or (iii); and
v) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (iii) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity.
73. A pharmaceutical composition comprising a vector comprising a nucleic acid molecule selected from a group consisting of
i) nucleic acid molecules encoding a polypeptide comprising the amino acid sequence of SEQ ID NO:2,
ii) nucleic acid molecules comprising the sequence of SEQ ID NO:1,
iii) nucleic acid molecules having the sequence of SEQ ID NO:1,
iv) nucleic acid molecules the complementary strand of which hybridizes under stringent conditions to a nucleic acid molecule of (i), (ii), or (iii); and
v) nucleic acid molecules the sequence of which differs from the sequence of a nucleic acid molecule of (iii) due to the degeneracy of the genetic code;
wherein the polypeptide encoded by the nucleic acid molecule has MGAT-X1 activity.
74. A pharmaceutical composition comprising a polypeptide selected from the group consisting of:
i) a polypeptide consisting of SEQ ID NO:2,
ii) a polypeptide comprising the sequence of SEQ ID NO:2,
iii) polypeptides encoded by nucleic acid molecules of claim 43; and
iv) polypeptides which show at least 99%, 98%, 95%, 90%, or 80% homology with a polypeptide of (i), (ii), or (iii);
wherein the polypeptide has MGAT-X1 activity.
75. A pharmaceutical composition comprising a regulator of MGAT-X1 selected from the group consisting of an RNA molecule, an antisense oligonucleotide, an antibody, or a ribozyme.