13G Filing: Jafco Sv4 Investment Limited Partnership and Miragen Therapeutics Inc. (NASDAQ:MGEN)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of
1934

(Amendment No. ________)*

Miragen Therapeutics, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

60463E103

(CUSIP Number)

February 13, 2017

(Date of Event Which Requires Filing of
this Statement)

Check the appropriate box to designate the rule pursuant
to which this Schedule is filed:

o
Rule 13d-1(b)

x Rule
13d-1(c)

o Rule
13d-1(d)

*The remainder of this cover page shall be filled out for a
reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page
shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”)
or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however,
see the Notes).

Persons who respond to the collection
of information contained in this form are not
required to respond unless the form displays a currently valid OMB control number.

13G

ITEM 1.

(a) Name of Issuer:
Miragen Therapeutics, Inc.

(b) Address of Issuer’s
Principal Executive Offices: 6200 Lookout Road, Boulder, CO 80301

ITEM 2.

(a) Name of Person
Filing: This Statement is filed by JAFCO SV4 Investment Limited Partnership (“JAFCO SV4”) and JAFCO Co., Ltd. (“JAFCO
Co., Ltd.”). The foregoing entities are collectively referred to as the “Reporting Persons.” JAFCO Co., Ltd.,
the general partner of JAFCO SV4, may be deemed to have sole power to vote and sole power to dispose of shares of the issuer directly
owned by JAFCO SV4.

(b) Address of Principal
Business Office, or if None, Residence: The address for each of the Reporting Persons is: Otemachi First Square West Tower 11F,
1-5-1, Otemachi Chiyoda-Ku Tokyo, Japan 100-0004

(c) Citizenship: The
citizenship of each of the Reporting Persons is Japan

(d) Title of Class
of Securities: Common Stock

(e) CUSIP Number:
60463E103

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT
TO SS.240.13d-1(b) OR 240.13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A: Not Applicable

ITEM 4. OWNERSHIP.

Provide the following information regarding
the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

(a) Amount beneficially
owned: 1,160,406 shares

(b) Percent of class:
5.4%

(c) Number of shares
as to which such person has:

(i) Sole power
to vote or to direct the vote: 1,160,406 shares (See Row 5 of cover page for each Reporting Person.)

(ii) Shared power
to vote or to direct the vote: See Row 6 of cover page for each Reporting Person.

(iii) Sole power
to dispose or to direct the disposition of: 1,160,406 shares (See Row 7 of cover page for each Reporting Person.)

(iv) Shared power
to dispose or to direct the disposition of: See Row 8 of cover page for each Reporting Person.

The percentages used
herein are calculated based on 21,370,063 shares of Common Stock reported by Miragen Therapeutics, Inc. issued and outstanding
as of March 17, 2017, as disclosed on the cover page of its Annual Report on Form 10-K, as filed with the Securities
and Exchange Commission on or about March 24, 2017.

ITEM 5. OWNERSHIP OF FIVE PERCENT OR
LESS OF A CLASS.

Not applicable.

ITEM 6. OWNERSHIP OF MORE THAN FIVE
PERCENT ON BEHALF OF ANOTHER PERSON.

Not Applicable.

ITEM 7. IDENTIFICATION AND CLASSIFICATION
OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

Not Applicable.

ITEM 8. IDENTIFICATION AND CLASSIFICATION
OF MEMBERS OF THE GROUP.

Not Applicable.

ITEM 9. NOTICE OF DISSOLUTION OF GROUP.

Not Applicable.

ITEM 10. CERTIFICATIONS.

(a) The following certification
shall be included if the statement is filed pursuant to Rule 13d-1(b):

“By signing below I certify
that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course
of business and were not acquired and not held for the purpose of or with the effect of changing or influencing the control of
the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having
such purpose or effect.”

(b) The following certification
shall be included if the statement is filed pursuant to Rule 13d-1(c):

“By signing below I certify
that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose
of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not
held in connection with or as a participant in any transaction having such purpose or effect.”

SIGNATURE

After reasonable inquiry and to the best
of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

March 31, 2017

(Date)

The original statement shall be signed
by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of
a person by his authorized representative other than an executive officer or general partner of the filing person, evidence of
the representative’s authority to sign on behalf of such person shall be filed with the statement, provided, however, that a power
of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title
of each person who signs the statement shall be typed or printed beneath his signature.

Exhibit A

Agreement of Joint Filing

The undersigned hereby
agree that a single Schedule 13G (or any amendment thereto) relating to the common stock of the Issuer shall be filed on behalf
of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G.

Date: March 31, 2017