Title: DELAYED SOMITE FORMATION IN A QUAIL LINE EXHIBITING MYOFIBER HYPERPLASIA IS ACCOMPANIED BY DELAYED EXPRESSION OF MYOGENIC REGULATORY FACTORS AND MYOSIN HEAVY-CHAIN

Author(s): COUTINHO LL , MORRIS J, MARKS HL, BUHR RJ, IVARIE R

Source:  DEVELOPMENT 117 (2): 563-569 FEB 1993

Document Type:  Article

Language:  English

Abstract:  A myofiber hyperplastic quail line P has been developed through selection for heavy body weight. Since the number of muscle fibers is determined early in development and skeletal muscle originates from somites, we compared somite formation and muscle-specific gene expression in P- and control C-line quail embryos. At 47 hours of incubation, C embryos had 18 somite pairs and P embryos had 14.3. By 72 and 120 hours, both lines appeared to be at the same stage of somite development. To determine whether the delay in the formation of the brachial somites was accompanied by alterations in muscle-specific gene expression, we conducted whole-mount in situ hybridization and immunofluorescence studies. At 47 hours of incubation, C embryos were expressing qmf1 in the first 12 somites, while in P embryos only the first 7 somites showed qmf1 activation. Delays in expression were also observed for qmf3 at 43 hours and for all three myogenic factors (qmf1, qmf2 and qmf3) at 60 hours. At 65 hours, C embryos expressed myosin heavy chain in the first 15 somite pairs and P embryos in the first 7. At 72 hours, the transient delay in somite formation had disappeared and there was no lag in myosin heavy chain expression between the lines. The phase delay in brachial somite formation, myogenic factors and myosin heavy chain expression may be associated with the observed myofiber hyperplasia in P-line quail by allowing an increase in the muscle stem cell population.

Author Keywords:  SOMITE; QMFL; BHLH; MYOGENIC FACTORS; MYOGENESIS; MYOSIN HEAVY CHAIN; COUTURNIX; QUAIL; HYPERPLASIA

KeyWords Plus:  LONG-TERM SELECTION; JAPANESE QUAIL; GENE FAMILY; AVIAN EMBRYOS; CELL LINEAGE; BODY-WEIGHT; MYOD FAMILY; MUSCLE; MUSCULATURE; ORIGIN

Addresses:  UNIV GEORGIA, DEPT GENET, ATHENS, GA 30602 USA
UNIV GEORGIA, DEPT POULTRY SCI, ATHENS, GA 30602 USA
USDA, ARS, SEPRL, ATHENS, GA 30602 USA

Publisher:  COMPANY OF BIOLOGISTS LTD, BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE, CAMBS, ENGLAND CB4 4DL

Subject Category:  DEVELOPMENTAL BIOLOGY

IDS Number:  KU455

ISSN:  0950-1991